chore(deps): update dependency urllib3 to v2.8.0 [security]

renovate-forgejo commented

2026-11-06 10:26:22 +00:00

Collaborator

This PR contains the following updates:

Package	Type	Update	Change
urllib3 (changelog)	uv.lock	minor	`2.6.3` → `2.8.0`

urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API

CVE-2026-44432 / GHSA-mf9v-mfxr-j63j / PYSEC-2026-142

More information

Details

Impact

urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once.

urllib3 can perform decompression based on the HTTP Content-Encoding header (e.g., gzip, deflate, br, or zstd). When using the streaming API since version 2.6.0, the library decompresses only the necessary bytes, enabling partial content consumption.

However, urllib3 before version 2.7.0 could still decompress the whole response instead of the requested portion in two cases:

During the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library.
When HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here).

These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data; CWE-409) on the client side.

Affected usages

Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected when streaming compressed responses from untrusted sources in either of these cases, unless decompression is explicitly disabled:

A response encoded with br is read incrementally with at least two HTTPResponse.read(amt=N) or HTTPResponse.stream(amt=N) calls while using the official Brotli library.
HTTPResponse.drain_conn() is called after response decompression has already started.

Remediation

Upgrade to at least urllib3 version 2.7.0 in which the library:

Is more efficient for reads with Brotli.
Always skips decompression for HTTPResponse.drain_conn().

If upgrading is not immediately possible, the following workarounds may reduce exposure in specific cases:

For the Brotli-specific issue only, switch from brotli to brotlicffi until you can upgrade urllib3; the official Brotli package is affected because of https://github.com/google/brotli/issues/1396.
If your code explicitly calls HTTPResponse.drain_conn(), call HTTPResponse.close() instead when connection reuse is not important.

Credits

The Brotli-specific issue was reported by @kimkou2024.
HTTPResponse.drain_conn() inefficiency was reported by @Cycloctane.

Severity

CVSS Score: 8.9 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

urllib3: Sensitive headers forwarded across origins in proxied low-level redirects

CVE-2026-44431 / GHSA-qccp-gfcp-xxvc / PYSEC-2026-141

More information

Details

Impact

When following cross-origin redirects for requests made using urllib3’s high-level APIs, such as urllib3.request(), PoolManager.request(), and ProxyManager.request(), sensitive headers — Authorization, Cookie, and Proxy-Authorization (defined in Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT) — are stripped by default, as expected.

However, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers.

Affected usage

Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected if they allow cross-origin redirects while making requests through HTTPConnection.urlopen() instances created via ProxyManager.connection_from_url().

Remediation

Upgrade to urllib3 version 2.7.0 or later, in which sensitive headers are stripped from redirects followed by HTTPConnection.

If upgrading is not immediately possible, avoid using this low-level redirect flow for cross-origin redirects. If appropriate for your use case, switch to ProxyManager.request().

Severity

CVSS Score: 8.2 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

CVE-2026-44431 / GHSA-qccp-gfcp-xxvc / PYSEC-2026-141

More information

Details

urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0.

Severity

CVSS Score: 5.3 / 10 (Medium)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc

This data is provided by OSV and the PyPI Advisory Database (CC-BY 4.0).

CVE-2026-44432 / GHSA-mf9v-mfxr-j63j / PYSEC-2026-142

More information

Details

urllib3 is an HTTP client library for Python. From 2.6.0 to before 2.7.0, urllib3 could decompress the whole response instead of the requested portion (1) during the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library or (2) when HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here). These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data) on the client side. This vulnerability is fixed in 2.7.0.

Severity

CVSS Score: 7.5 / 10 (High)
Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References

https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j

This data is provided by OSV and the PyPI Advisory Database (CC-BY 4.0).

urllib3: HTTPS proxy TLS configuration may be ignored or overridden

CVE-2026-97687 / GHSA-8988-9cw3-xx77 / PYSEC-2026-4175

More information

Details

Impact

urllib3 supports configuring TLS independently for an HTTPS proxy and the target server.

proxy_ssl_context, proxy_assert_hostname, and proxy_assert_fingerprint configure the TLS connection to the proxy. ssl_context and the other target-specific TLS parameters configure the connection to the target server.

In urllib3 versions 1.26.0 through 2.7.0, these configurations were not consistently separated. Depending on the proxy mode, urllib3 could:

Ignore proxy_ssl_context and use the target server's SSL context for the TLS connection to an HTTPS forwarding proxy.
Override the HTTPS proxy's certificate-verification policy with the target server's certificate-verification policy.
Apply target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials to the TLS connection to an HTTPS forwarding proxy.

In particular, configuring cert_reqs="CERT_NONE" for a target server could overwrite the verify_mode of the SSL context configured for the HTTPS proxy. This modification occurred in place and persisted on the context object, potentially disabling proxy certificate verification for later connections that reused the same context.

An attacker able to intercept the connection to an HTTPS proxy may be able to impersonate the proxy when the effective proxy TLS configuration disables certificate verification or otherwise accepts the attacker's certificate. This may occur, for example, when the target server's trust or identity policy is incorrectly applied to the proxy connection.

When HTTPS forwarding is enabled, an impersonated proxy can observe or modify forwarded requests and responses, potentially exposing credentials, authentication tokens, request bodies, response data, and other sensitive information.

A TLS client certificate intended for the target server may also be presented to the proxy or to an attacker impersonating it. This can disclose the client's identity and provide proof of possession of the corresponding private key. The private key itself is not transmitted during the TLS handshake.

In CONNECT tunneling mode, impersonating the HTTPS proxy does not by itself defeat the separate end-to-end TLS connection between the client and the target server.

Affected Usages

Code using urllib3 versions 1.26.0 through 2.7.0 may be affected in any of the following cases.

1. The target SSL context is used for an HTTPS forwarding proxy

HTTPS requests are forwarded through an HTTPS proxy with use_forwarding_for_https=True, and proxy_ssl_context is configured for the proxy.

urllib3 may ignore proxy_ssl_context and use the target server's ssl_context for the proxy TLS handshake. The proxy may therefore be verified using the target server's trust and certificate policy instead of the policy explicitly configured for the proxy.

2. The target verification policy overrides the proxy policy

An HTTPS proxy is configured with proxy_ssl_context, while the target server uses a different certificate-verification policy.

urllib3 may apply the target server's cert_reqs value to the proxy SSL context. For example, setting cert_reqs="CERT_NONE" for the target server may also disable certificate verification for the HTTPS proxy, even when proxy_ssl_context was configured to require verification.

This issue can affect the TLS connection to an HTTPS proxy in both forwarding and CONNECT tunneling configurations.

3. A mutated proxy SSL context is reused

The same SSL context is reused as proxy_ssl_context across multiple connections, and certificate verification is disabled for one target server.

urllib3 may modify the proxy SSL context's verify_mode in place. Later connections that reuse the same context may therefore connect to the HTTPS proxy without certificate verification.

4. Target-specific TLS identity or credentials are applied to the proxy

HTTPS requests are forwarded through an HTTPS proxy with use_forwarding_for_https=True, and target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials are configured.

urllib3 may apply these target-specific settings to the proxy TLS handshake. This may cause urllib3 to:

send SNI intended for the target server to the proxy;
verify the proxy using a hostname or certificate fingerprint intended for the target server; or
present a TLS client certificate intended for the target server to the proxy.

Code connecting through a plain HTTP proxy does not establish a TLS connection to the proxy and is not affected by this issue.

Remediation

Upgrade to urllib3 2.8.0 or later.

urllib3 2.8.0 independently applies the explicitly configured proxy_ssl_context and proxy-specific certificate assertions to the HTTPS proxy connection. Target-specific SNI, certificate assertions, and TLS client certificate parameters are no longer applied to the HTTPS proxy handshake.

For backward compatibility, when an HTTPS proxy is used with use_forwarding_for_https=True and proxy_ssl_context is not provided, urllib3 2.8.0 continues to use ssl_context for the TLS connection to the proxy. This configuration emits a FutureWarning. In urllib3 3.0, passing ssl_context with use_forwarding_for_https=True for an HTTPS proxy will raise an error. Applications should use proxy_ssl_context to configure TLS for an HTTPS forwarding proxy.

The fixes were implemented in commits b6447295fff7b38fdffc67e0df9712d60cef3cc3 and 07408cec79d1856d81bb42c74a904a24fdb9e465.

Severity

CVSS Score: 7.6 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

urllib3: Chunked Deflate streaming can enter an infinite loop

CVE-2026-97688 / GHSA-gh4c-6fx4-qh6g / PYSEC-2026-4176

More information

Details

Impact

urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading content in chunks instead of loading the entire response body into memory at once.

urllib3 can decompress response bodies according to the HTTP Content-Encoding header. When streaming a compressed, chunked response, urllib3 first consumes data already buffered by the decoder before reading the next HTTP chunk.

However, urllib3 versions from 2.6.2 through 2.7.0 could enter an infinite loop when a chunked response contained bytes after the end of the Deflate stream. If the decompressed body exceeded the requested streaming chunk size, Python's zlib implementation could retain the trailing bytes as unconsumed input after reaching the end of the compressed stream. urllib3 would repeatedly attempt to decode those same bytes without making progress or reading more data from the network.

A malicious server could exploit this behavior to cause excessive CPU usage and prevent the affected request from completing on the client. Network read timeouts would not interrupt the loop because no further socket operation was required.

Affected usages

Applications and libraries using urllib3 versions 2.6.2 through 2.7.0 may be affected when all of the following conditions are met:

Compressed responses from an untrusted source are streamed using HTTPResponse.stream(amt=N) or HTTPResponse.read_chunked(amt=N) with a positive, finite chunk size.
Content decoding is enabled.
The response uses both Transfer-Encoding: chunked and Content-Encoding: deflate.
The decoded body exceeds the requested chunk size and the encoded body contains bytes after the end of the Deflate stream.

HTTPResponse.stream() uses a finite chunk size by default and is therefore affected when the other conditions are met.

Remediation

Upgrade to urllib3 2.8.0, in which the Deflate decoder stops accepting input after reaching the end of the compressed stream and no longer reports trailing bytes as data that can produce more decoded output.

If upgrading is not immediately possible, disable automatic content decoding for responses from untrusted sources by setting decode_content=False, or reject streamed responses using the Deflate content encoding. Applications that disable automatic decoding must handle the compressed response safely at another layer.

Severity

CVSS Score: 6.9 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory

CVE-2026-97689 / GHSA-vxq7-64xx-v4gw / PYSEC-2026-4177

More information

Details

Impact

urllib3's streaming API is designed for efficiently handling large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. When decoding a chunked-transfer-encoded response, this API reads each chunk's size field by buffering until it sees \n or EOF.

A malicious HTTP server can return Transfer-Encoding: chunked and then send a very long run of bytes without any newline, causing the streaming client to buffer that entire run before urllib3 can reject the chunk size as invalid and allocate more memory than intended.

To fix the issue, we'll reject chunk-size fields larger than 65536 bytes, as already done in the non-streaming case, which is currently handled by the Python standard library. Note that this only applies to reading the chunk-size field, not the chunk data, which is already handled correctly. Thus, there shouldn't be any impact for non-malicious servers.

Affected usages

Applications and libraries using urllib3 versions earlier than 2.8.0 may be affected when streaming a chunked response from untrusted sources. Specifically, this affects the read_chunked() and stream() methods of the HTTPResponse object.

This also affects requests streaming API, which uses urllib3 under the hood.

Remediation

Upgrade to urllib3 version 2.8.0 or later, where chunk-size fields larger than 65536 will be rejected. If upgrading is not immediately possible, consider reading the response at once using the read() method.

Severity

CVSS Score: 8.9 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

References

This data is provided by OSV and the GitHub Advisory Database (CC-BY 4.0).

urllib3: HTTPS proxy TLS configuration may be ignored or overridden

CVE-2026-97687 / GHSA-8988-9cw3-xx77 / PYSEC-2026-4175

More information

Details

Impact

urllib3 supports configuring TLS independently for an HTTPS proxy and the target server.

proxy_ssl_context, proxy_assert_hostname, and proxy_assert_fingerprint configure the TLS connection to the proxy. ssl_context and the other target-specific TLS parameters configure the connection to the target server.

In urllib3 versions 1.26.0 through 2.7.0, these configurations were not consistently separated. Depending on the proxy mode, urllib3 could:

Ignore proxy_ssl_context and use the target server's SSL context for the TLS connection to an HTTPS forwarding proxy.
Override the HTTPS proxy's certificate-verification policy with the target server's certificate-verification policy.
Apply target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials to the TLS connection to an HTTPS forwarding proxy.

In particular, configuring cert_reqs="CERT_NONE" for a target server could overwrite the verify_mode of the SSL context configured for the HTTPS proxy. This modification occurred in place and persisted on the context object, potentially disabling proxy certificate verification for later connections that reused the same context.

An attacker able to intercept the connection to an HTTPS proxy may be able to impersonate the proxy when the effective proxy TLS configuration disables certificate verification or otherwise accepts the attacker's certificate. This may occur, for example, when the target server's trust or identity policy is incorrectly applied to the proxy connection.

When HTTPS forwarding is enabled, an impersonated proxy can observe or modify forwarded requests and responses, potentially exposing credentials, authentication tokens, request bodies, response data, and other sensitive information.

A TLS client certificate intended for the target server may also be presented to the proxy or to an attacker impersonating it. This can disclose the client's identity and provide proof of possession of the corresponding private key. The private key itself is not transmitted during the TLS handshake.

In CONNECT tunneling mode, impersonating the HTTPS proxy does not by itself defeat the separate end-to-end TLS connection between the client and the target server.

Affected Usages

Code using urllib3 versions 1.26.0 through 2.7.0 may be affected in any of the following cases.

1. The target SSL context is used for an HTTPS forwarding proxy

HTTPS requests are forwarded through an HTTPS proxy with use_forwarding_for_https=True, and proxy_ssl_context is configured for the proxy.

urllib3 may ignore proxy_ssl_context and use the target server's ssl_context for the proxy TLS handshake. The proxy may therefore be verified using the target server's trust and certificate policy instead of the policy explicitly configured for the proxy.

2. The target verification policy overrides the proxy policy

An HTTPS proxy is configured with proxy_ssl_context, while the target server uses a different certificate-verification policy.

urllib3 may apply the target server's cert_reqs value to the proxy SSL context. For example, setting cert_reqs="CERT_NONE" for the target server may also disable certificate verification for the HTTPS proxy, even when proxy_ssl_context was configured to require verification.

This issue can affect the TLS connection to an HTTPS proxy in both forwarding and CONNECT tunneling configurations.

3. A mutated proxy SSL context is reused

The same SSL context is reused as proxy_ssl_context across multiple connections, and certificate verification is disabled for one target server.

urllib3 may modify the proxy SSL context's verify_mode in place. Later connections that reuse the same context may therefore connect to the HTTPS proxy without certificate verification.

4. Target-specific TLS identity or credentials are applied to the proxy

HTTPS requests are forwarded through an HTTPS proxy with use_forwarding_for_https=True, and target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials are configured.

urllib3 may apply these target-specific settings to the proxy TLS handshake. This may cause urllib3 to:

send SNI intended for the target server to the proxy;
verify the proxy using a hostname or certificate fingerprint intended for the target server; or
present a TLS client certificate intended for the target server to the proxy.

Code connecting through a plain HTTP proxy does not establish a TLS connection to the proxy and is not affected by this issue.

Remediation

Upgrade to urllib3 2.8.0 or later.

urllib3 2.8.0 independently applies the explicitly configured proxy_ssl_context and proxy-specific certificate assertions to the HTTPS proxy connection. Target-specific SNI, certificate assertions, and TLS client certificate parameters are no longer applied to the HTTPS proxy handshake.

For backward compatibility, when an HTTPS proxy is used with use_forwarding_for_https=True and proxy_ssl_context is not provided, urllib3 2.8.0 continues to use ssl_context for the TLS connection to the proxy. This configuration emits a FutureWarning. In urllib3 3.0, passing ssl_context with use_forwarding_for_https=True for an HTTPS proxy will raise an error. Applications should use proxy_ssl_context to configure TLS for an HTTPS forwarding proxy.

The fixes were implemented in commits b6447295fff7b38fdffc67e0df9712d60cef3cc3 and 07408cec79d1856d81bb42c74a904a24fdb9e465.

Severity

CVSS Score: 7.6 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References

This data is provided by OSV and the PyPI Advisory Database (CC-BY 4.0).

urllib3: Chunked Deflate streaming can enter an infinite loop

CVE-2026-97688 / GHSA-gh4c-6fx4-qh6g / PYSEC-2026-4176

More information

Details

Impact

urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading content in chunks instead of loading the entire response body into memory at once.

urllib3 can decompress response bodies according to the HTTP Content-Encoding header. When streaming a compressed, chunked response, urllib3 first consumes data already buffered by the decoder before reading the next HTTP chunk.

However, urllib3 versions from 2.6.2 through 2.7.0 could enter an infinite loop when a chunked response contained bytes after the end of the Deflate stream. If the decompressed body exceeded the requested streaming chunk size, Python's zlib implementation could retain the trailing bytes as unconsumed input after reaching the end of the compressed stream. urllib3 would repeatedly attempt to decode those same bytes without making progress or reading more data from the network.

A malicious server could exploit this behavior to cause excessive CPU usage and prevent the affected request from completing on the client. Network read timeouts would not interrupt the loop because no further socket operation was required.

Affected usages

Applications and libraries using urllib3 versions 2.6.2 through 2.7.0 may be affected when all of the following conditions are met:

Compressed responses from an untrusted source are streamed using HTTPResponse.stream(amt=N) or HTTPResponse.read_chunked(amt=N) with a positive, finite chunk size.
Content decoding is enabled.
The response uses both Transfer-Encoding: chunked and Content-Encoding: deflate.
The decoded body exceeds the requested chunk size and the encoded body contains bytes after the end of the Deflate stream.

HTTPResponse.stream() uses a finite chunk size by default and is therefore affected when the other conditions are met.

Remediation

Upgrade to urllib3 2.8.0, in which the Deflate decoder stops accepting input after reaching the end of the compressed stream and no longer reports trailing bytes as data that can produce more decoded output.

If upgrading is not immediately possible, disable automatic content decoding for responses from untrusted sources by setting decode_content=False, or reject streamed responses using the Deflate content encoding. Applications that disable automatic decoding must handle the compressed response safely at another layer.

Severity

CVSS Score: 6.9 / 10 (Medium)
Vector String: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

References

This data is provided by OSV and the PyPI Advisory Database (CC-BY 4.0).

urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory

CVE-2026-97689 / GHSA-vxq7-64xx-v4gw / PYSEC-2026-4177

More information

Details

Impact

urllib3's streaming API is designed for efficiently handling large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. When decoding a chunked-transfer-encoded response, this API reads each chunk's size field by buffering until it sees \n or EOF.

A malicious HTTP server can return Transfer-Encoding: chunked and then send a very long run of bytes without any newline, causing the streaming client to buffer that entire run before urllib3 can reject the chunk size as invalid and allocate more memory than intended.

To fix the issue, we'll reject chunk-size fields larger than 65536 bytes, as already done in the non-streaming case, which is currently handled by the Python standard library. Note that this only applies to reading the chunk-size field, not the chunk data, which is already handled correctly. Thus, there shouldn't be any impact for non-malicious servers.

Affected usages

Applications and libraries using urllib3 versions earlier than 2.8.0 may be affected when streaming a chunked response from untrusted sources. Specifically, this affects the read_chunked() and stream() methods of the HTTPResponse object.

This also affects requests streaming API, which uses urllib3 under the hood.

Remediation

Upgrade to urllib3 version 2.8.0 or later, where chunk-size fields larger than 65536 will be rejected. If upgrading is not immediately possible, consider reading the response at once using the read() method.

Severity

CVSS Score: 8.9 / 10 (High)
Vector String: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H

References

This data is provided by OSV and the PyPI Advisory Database (CC-BY 4.0).

Release Notes

urllib3/urllib3 (urllib3)

`v2.8.0`

Compare Source

==================

Security

Fixed the following security issues:

The TLS configuration for HTTPS proxies could be ignored or overridden.
(High severity, GHSA-8988-9cw3-xx77 <https://github.com/urllib3/urllib3/security/advisories/GHSA-8988-9cw3-xx77>__)
HTTPResponse.stream() and read_chunked() could buffer a chunk-size
line of unbounded length in memory. (High severity,
GHSA-vxq7-64xx-v4gw <https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw>__)
Chunked Deflate streaming could enter an infinite loop. (Medium severity,
GHSA-gh4c-6fx4-qh6g <https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g>__)

.. caution::

urllib3 2.8.0 fixes HTTPS proxy TLS configuration being ignored or
overridden by destination settings. Configurations relying on that
behavior may require changes.

Configure proxy CA certificates and client certificates in
``proxy_ssl_context``, and proxy identity checks with
``proxy_assert_hostname`` or ``proxy_assert_fingerprint``.
Destination client certificates and identity overrides no longer
apply to HTTPS forwarding proxy connections.

Deprecations & Removals

Deprecated using an empty collection as the Retry option
allowed_methods to retry any verb.
(#5044 <https://github.com/urllib3/urllib3/issues/5044>__)

Features

Added Url.auth_decoded and Url.auth_decoded_joined convenience
properties to the result of parse_url().
(#4945 <https://github.com/urllib3/urllib3/issues/4945>__)
Added basic_auth_encoding and proxy_basic_auth_encoding parameters to
urllib3.util.make_headers().
(#5092 <https://github.com/urllib3/urllib3/issues/5092>__)

Bugfixes

Fixed response header handling to replace obsolete folded header lines
(obs-fold) with spaces in accordance with RFC 9112, preventing raw CRLF
sequences from appearing in header values such as Set-Cookie.
(#1362 <https://github.com/urllib3/urllib3/issues/1362>__)
Fixed usage of proxy_ssl_context with ProxyManager when
use_forwarding_for_https=True. Passing ssl_context instead of
proxy_ssl_context for HTTPS proxies in this configuration now emits a
FutureWarning and will raise an error in v3.0.
(#2577 <https://github.com/urllib3/urllib3/issues/2577>__)
Changed behavior of the default ConnectionPool.pool initialization.
LifoQueue is now resolved from the queue module after the
ConnectionPool is instantiated instead of using the default cached
QueueCls class property. This is done because sometimes the
queue.LifoQueue is monkey-patched late in the program, such as by gevent.
(#3289 <https://github.com/urllib3/urllib3/issues/3289>__)
Raised UnrewindableBodyError instead of ValueError when retrying a
request whose body had tell() but not seek().
(#3779 <https://github.com/urllib3/urllib3/issues/3779>__)
Decoded percent-encoded SOCKS proxy credentials before authenticating with
the proxy server.
(#3785 <https://github.com/urllib3/urllib3/issues/3785>__)
Fixed HTTPResponse.drain_conn() to discard unread response data in 64 KiB
chunks (same as the default amt when doing HTTPResponse.stream(...)).
(#5019 <https://github.com/urllib3/urllib3/issues/5019>__)
Fixed is_ipaddress() to detect non-standard IPv4 forms accepted by
socket.connect, such as hex (0x7f000001), octal (0177.0.0.1), and
decimal integers (2130706433), ensuring SSL certificate verification uses
the correct mode for these addresses.
(#5029 <https://github.com/urllib3/urllib3/issues/5029>__)
Fixed HTTPConnectionPool.urlopen raising a misleading FullPoolError
instead of ValueError when called with an invalid timeout argument on
a pool created with block=True.
(#5059 <https://github.com/urllib3/urllib3/issues/5059>__)
Fixed port-zero handling to preserve explicit :0 values instead of
substituting the default ports 80 or 443 in URL parsing, pool selection,
proxy configuration, connection_from_url(), and HTTP/2 request authority.
(#5071 <https://github.com/urllib3/urllib3/issues/5071>,
#5101 <https://github.com/urllib3/urllib3/issues/5101>)
Fixed a bug where PoolManager passed the assert_hostname and
assert_fingerprint parameters to HTTP connection pools.
(#5077 <https://github.com/urllib3/urllib3/issues/5077>__)
Fixed HTTPConnectionPool.urlopen() and HTTP proxy forwarding to strip URL
fragments from absolute request targets before sending requests.
(#5079 <https://github.com/urllib3/urllib3/issues/5079>__)
Added safeguards to the proxy tunneling code to prevent potential security
issues when handling invalid characters in the proxy host and HTTP headers.
This change affects users of Python 3.10, Python 3.11, and Python 3.12 when
the standard library does not contain the fix; those on newer Python versions
should upgrade to 3.13.14+ or 3.14.5+ to get the same security fixes.
(#5091 <https://github.com/urllib3/urllib3/issues/5091>__)
Fixed HTTPSConnection.connect() overriding ProxyConfig.ssl_context's
certificate policy and proxy identity checks with the target connection's TLS
settings when forwarding through an HTTPS proxy.

HTTPSConnection no longer applies target SNI, assertions, or client
credentials to forwarding proxy handshakes and continues to use its
ssl_context as a fallback when an HTTPS proxy forwards an HTTP target.
(#5093 <https://github.com/urllib3/urllib3/issues/5093>__)
Fixed URL parsing to more strictly enforce RFC 3986 host syntax, rejecting
invalid host input such as raw spaces and control characters, malformed
percent-encodings, and percent-encoded control characters in HTTP(S) hosts
and IPv6 zone identifiers, including proxy CONNECT tunnel targets. Host
normalization now also follows RFC 3986 normalization rules for
percent-encoded octets by decoding percent-encoded unreserved characters and
uppercasing the hexadecimal digits of retained percent-encoded octets.
(#5095 <https://github.com/urllib3/urllib3/issues/5095>__)
Fixed an AttributeError on Python built with OpenSSL 4+, where
ssl.PROTOCOL_TLSv1 no longer exists.
(#5097 <https://github.com/urllib3/urllib3/issues/5097>__)
Fixed urllib3.contrib.pyopenssl to use cryptography APIs when reading a
certificate subject and loading encrypted private keys, avoiding
DeprecationWarning raised by pyOpenSSL 26.3.0+.
(#5103 <https://github.com/urllib3/urllib3/issues/5103>__)
Fixed handling of HTTP 303 redirects for requests with chunked or file-like
bodies.
(#5161 <https://github.com/urllib3/urllib3/issues/5161>__)
Fixed assert_fingerprint() to raise SSLError instead of
binascii.Error when a fingerprint has a supported length but contains
non-hexadecimal characters.
(#5211 <https://github.com/urllib3/urllib3/issues/5211>__)

Misc

Added a test dependency group containing the minimum dependencies needed
to run the test suite, intended for downstream packagers. The dev-base
and mypy groups now include this new group via include-group,
removing duplication.
(#3594 <https://github.com/urllib3/urllib3/issues/3594>__)
Fixed test failures with pytest >= 9.1.
(#5094 <https://github.com/urllib3/urllib3/issues/5094>__)
Enabled JSPI tests with Firefox in the Emscripten test suite.
(#5166 <https://github.com/urllib3/urllib3/issues/5166>__)
Improved streamed response decoding performance.
(#5209 <https://github.com/urllib3/urllib3/issues/5209>__)
Fixed flaky tests.
(#5232 <https://github.com/urllib3/urllib3/issues/5232>,
#5234 <https://github.com/urllib3/urllib3/issues/5234>,
#5239 <https://github.com/urllib3/urllib3/issues/5239>__)

`v2.7.0`

Compare Source

=======================

Security

Addressed high-severity security issues.
Impact was limited to specific use cases detailed in the accompanying
advisories; overall user exposure was estimated to be marginal.

Decompression-bomb safeguards of the streaming API were bypassed:
1. When HTTPResponse.drain_conn() was called after the response had been
  read and decompressed partially.
2. During the second HTTPResponse.read(amt=N) or
  HTTPResponse.stream(amt=N) call when the response was decompressed
  using the official Brotli <https://pypi.org/project/brotli/>__ library.
See GHSA-mf9v-mfxr-j63j <https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j>__
for details.
HTTP pools created using ProxyManager.connection_from_url did not strip
sensitive headers specified in Retry.remove_headers_on_redirect when
redirecting to a different host.
(GHSA-qccp-gfcp-xxvc <https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc>__)

Deprecations and Removals

Used FutureWarning instead of DeprecationWarning for better
visibility of existing deprecation notices. Rescheduled the removal of
deprecated features to version 3.0.
(#3763 <https://github.com/urllib3/urllib3/issues/3763>__)
Removed support for end-of-life Python 3.9.
(#3720 <https://github.com/urllib3/urllib3/issues/3720>__)
Removed support for end-of-life PyPy3.10.
(#4979 <https://github.com/urllib3/urllib3/issues/4979>__)
Bumped the minimum supported pyOpenSSL version to 19.0.0.
(#3777 <https://github.com/urllib3/urllib3/issues/3777>__)

Bugfixes

Fixed a bug where HTTPResponse.read(amt=None) was ignoring decompressed
data buffered from previous partial reads.
(#3636 <https://github.com/urllib3/urllib3/issues/3636>__)
Fixed a bug where HTTPResponse.read() could cache only part of the
response after a partial read when cache_content=True.
(#4967 <https://github.com/urllib3/urllib3/issues/4967>__)
Fixed HTTPResponse.stream() and HTTPResponse.read_chunked() to handle
amt=0.
(#3793 <https://github.com/urllib3/urllib3/issues/3793>__)
Updated _TYPE_BODY type alias to include missing Iterable[str],
matching the documented and runtime behavior of chunked request bodies.
(#3798 <https://github.com/urllib3/urllib3/issues/3798>__)
Fixed LocationParseError when paths resembling schemeless URIs were
passed to HTTPConnectionPool.urlopen().
(#3352 <https://github.com/urllib3/urllib3/issues/3352>__)
Fixed BaseHTTPResponse.readinto() type annotation to accept
memoryview in addition to bytearray, matching the
io.RawIOBase.readinto contract and enabling use with
io.BufferedReader without type errors.
(#3764 <https://github.com/urllib3/urllib3/issues/3764>__)

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This PR contains the following updates: | Package | Type | Update | Change | |---|---|---|---| | [urllib3](https://github.com/urllib3/urllib3) ([changelog](https://github.com/urllib3/urllib3/blob/main/CHANGES.rst)) | uv.lock | minor | `2.6.3` → `2.8.0` | --- ### urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API [CVE-2026-44432](https://nvd.nist.gov/vuln/detail/CVE-2026-44432) / [GHSA-mf9v-mfxr-j63j](https://github.com/advisories/GHSA-mf9v-mfxr-j63j) / PYSEC-2026-142 <details> <summary>More information</summary> #### Details ##### Impact urllib3's [streaming API](https://urllib3.readthedocs.io/en/2.7.0/advanced-usage.html#streaming-and-i-o) is designed for the efficient handling of large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. urllib3 can perform decompression based on the HTTP `Content-Encoding` header (e.g., `gzip`, `deflate`, `br`, or `zstd`). When using the streaming API since version 2.6.0, the library decompresses only the necessary bytes, enabling partial content consumption. However, urllib3 before version 2.7.0 could still decompress the whole response instead of the requested portion in two cases: 1. During the second `HTTPResponse.read(amt=N)` call when the response was decompressed using the official [Brotli](https://pypi.org/project/brotli/) library. 2. When `HTTPResponse.drain_conn()` was called after the response had been read and decompressed partially (compression algorithm did not matter here). These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data; CWE-409) on the client side. ##### Affected usages Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected when streaming compressed responses from untrusted sources in either of these cases, unless decompression is explicitly disabled: 1. A response encoded with `br` is read incrementally with at least two `HTTPResponse.read(amt=N)` or `HTTPResponse.stream(amt=N)` calls while using the official [Brotli](https://pypi.org/project/brotli/) library. 2. `HTTPResponse.drain_conn()` is called after response decompression has already started. ##### Remediation Upgrade to at least urllib3 version 2.7.0 in which the library: 1. Is more efficient for reads with Brotli. 2. Always skips decompression for `HTTPResponse.drain_conn()`. If upgrading is not immediately possible, the following workarounds may reduce exposure in specific cases: 1. For the Brotli-specific issue only, switch from [brotli](https://pypi.org/project/brotli/) to [brotlicffi](https://pypi.org/project/brotlicffi/) until you can upgrade urllib3; the official Brotli package is affected because of https://github.com/google/brotli/issues/1396. 2. If your code explicitly calls `HTTPResponse.drain_conn()`, call `HTTPResponse.close()` instead when connection reuse is not important. ##### Credits The Brotli-specific issue was reported by @kimkou2024. `HTTPResponse.drain_conn()` inefficiency was reported by @Cycloctane. #### Severity - CVSS Score: 8.9 / 10 (High) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j](https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j) - [https://nvd.nist.gov/vuln/detail/CVE-2026-44432](https://nvd.nist.gov/vuln/detail/CVE-2026-44432) - [https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2026-142.yaml](https://github.com/pypa/advisory-database/tree/main/vulns/urllib3/PYSEC-2026-142.yaml) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-mf9v-mfxr-j63j) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)). </details> --- ### urllib3: Sensitive headers forwarded across origins in proxied low-level redirects [CVE-2026-44431](https://nvd.nist.gov/vuln/detail/CVE-2026-44431) / [GHSA-qccp-gfcp-xxvc](https://github.com/advisories/GHSA-qccp-gfcp-xxvc) / PYSEC-2026-141 <details> <summary>More information</summary> #### Details ##### Impact When following cross-origin redirects for requests made using urllib3’s high-level APIs, such as `urllib3.request()`, `PoolManager.request()`, and `ProxyManager.request()`, sensitive headers — `Authorization`, `Cookie`, and `Proxy-Authorization` (defined in `Retry.DEFAULT_REMOVE_HEADERS_ON_REDIRECT`) — are stripped by default, as expected. However, cross-origin redirects followed from the low-level API via `ProxyManager.connection_from_url().urlopen(..., assert_same_host=False)` still forward these sensitive headers. ##### Affected usage Applications and libraries using urllib3 versions earlier than 2.7.0 may be affected if they allow cross-origin redirects while making requests through `HTTPConnection.urlopen()` instances created via `ProxyManager.connection_from_url()`. ##### Remediation Upgrade to urllib3 version 2.7.0 or later, in which sensitive headers are stripped from redirects followed by `HTTPConnection`. If upgrading is not immediately possible, avoid using this low-level redirect flow for cross-origin redirects. If appropriate for your use case, switch to `ProxyManager.request()`. #### Severity - CVSS Score: 8.2 / 10 (High) - Vector String: `CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc](https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc) - [https://nvd.nist.gov/vuln/detail/CVE-2026-44431](https://nvd.nist.gov/vuln/detail/CVE-2026-44431) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-qccp-gfcp-xxvc) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)). </details> --- ### [CVE-2026-44431](https://nvd.nist.gov/vuln/detail/CVE-2026-44431) / [GHSA-qccp-gfcp-xxvc](https://github.com/advisories/GHSA-qccp-gfcp-xxvc) / PYSEC-2026-141 <details> <summary>More information</summary> #### Details urllib3 is an HTTP client library for Python. From 1.23 to before 2.7.0, cross-origin redirects followed from the low-level API via ProxyManager.connection_from_url().urlopen(..., assert_same_host=False) still forward these sensitive headers. This vulnerability is fixed in 2.7.0. #### Severity - CVSS Score: 5.3 / 10 (Medium) - Vector String: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc](https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc) This data is provided by [OSV](https://osv.dev/vulnerability/PYSEC-2026-141) and the [PyPI Advisory Database](https://github.com/pypa/advisory-database) ([CC-BY 4.0](https://github.com/pypa/advisory-database/blob/main/LICENSE)). </details> --- ### [CVE-2026-44432](https://nvd.nist.gov/vuln/detail/CVE-2026-44432) / [GHSA-mf9v-mfxr-j63j](https://github.com/advisories/GHSA-mf9v-mfxr-j63j) / PYSEC-2026-142 <details> <summary>More information</summary> #### Details urllib3 is an HTTP client library for Python. From 2.6.0 to before 2.7.0, urllib3 could decompress the whole response instead of the requested portion (1) during the second HTTPResponse.read(amt=N) call when the response was decompressed using the official Brotli library or (2) when HTTPResponse.drain_conn() was called after the response had been read and decompressed partially (compression algorithm did not matter here). These issues could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This could result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data) on the client side. This vulnerability is fixed in 2.7.0. #### Severity - CVSS Score: 7.5 / 10 (High) - Vector String: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j](https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j) This data is provided by [OSV](https://osv.dev/vulnerability/PYSEC-2026-142) and the [PyPI Advisory Database](https://github.com/pypa/advisory-database) ([CC-BY 4.0](https://github.com/pypa/advisory-database/blob/main/LICENSE)). </details> --- ### urllib3: HTTPS proxy TLS configuration may be ignored or overridden [CVE-2026-97687](https://nvd.nist.gov/vuln/detail/CVE-2026-97687) / [GHSA-8988-9cw3-xx77](https://github.com/advisories/GHSA-8988-9cw3-xx77) / PYSEC-2026-4175 <details> <summary>More information</summary> #### Details ##### Impact urllib3 supports configuring TLS independently for an HTTPS proxy and the target server. `proxy_ssl_context`, `proxy_assert_hostname`, and `proxy_assert_fingerprint` configure the TLS connection to the proxy. `ssl_context` and the other target-specific TLS parameters configure the connection to the target server. In urllib3 versions 1.26.0 through 2.7.0, these configurations were not consistently separated. Depending on the proxy mode, urllib3 could: 1. Ignore `proxy_ssl_context` and use the target server's SSL context for the TLS connection to an HTTPS forwarding proxy. 2. Override the HTTPS proxy's certificate-verification policy with the target server's certificate-verification policy. 3. Apply target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials to the TLS connection to an HTTPS forwarding proxy. In particular, configuring `cert_reqs="CERT_NONE"` for a target server could overwrite the `verify_mode` of the SSL context configured for the HTTPS proxy. This modification occurred in place and persisted on the context object, potentially disabling proxy certificate verification for later connections that reused the same context. An attacker able to intercept the connection to an HTTPS proxy may be able to impersonate the proxy when the effective proxy TLS configuration disables certificate verification or otherwise accepts the attacker's certificate. This may occur, for example, when the target server's trust or identity policy is incorrectly applied to the proxy connection. When HTTPS forwarding is enabled, an impersonated proxy can observe or modify forwarded requests and responses, potentially exposing credentials, authentication tokens, request bodies, response data, and other sensitive information. A TLS client certificate intended for the target server may also be presented to the proxy or to an attacker impersonating it. This can disclose the client's identity and provide proof of possession of the corresponding private key. The private key itself is not transmitted during the TLS handshake. In CONNECT tunneling mode, impersonating the HTTPS proxy does not by itself defeat the separate end-to-end TLS connection between the client and the target server. ##### Affected Usages Code using urllib3 versions 1.26.0 through 2.7.0 may be affected in any of the following cases. ##### 1. The target SSL context is used for an HTTPS forwarding proxy HTTPS requests are forwarded through an HTTPS proxy with `use_forwarding_for_https=True`, and `proxy_ssl_context` is configured for the proxy. urllib3 may ignore `proxy_ssl_context` and use the target server's `ssl_context` for the proxy TLS handshake. The proxy may therefore be verified using the target server's trust and certificate policy instead of the policy explicitly configured for the proxy. ##### 2. The target verification policy overrides the proxy policy An HTTPS proxy is configured with `proxy_ssl_context`, while the target server uses a different certificate-verification policy. urllib3 may apply the target server's `cert_reqs` value to the proxy SSL context. For example, setting `cert_reqs="CERT_NONE"` for the target server may also disable certificate verification for the HTTPS proxy, even when `proxy_ssl_context` was configured to require verification. This issue can affect the TLS connection to an HTTPS proxy in both forwarding and CONNECT tunneling configurations. ##### 3. A mutated proxy SSL context is reused The same SSL context is reused as `proxy_ssl_context` across multiple connections, and certificate verification is disabled for one target server. urllib3 may modify the proxy SSL context's `verify_mode` in place. Later connections that reuse the same context may therefore connect to the HTTPS proxy without certificate verification. ##### 4. Target-specific TLS identity or credentials are applied to the proxy HTTPS requests are forwarded through an HTTPS proxy with `use_forwarding_for_https=True`, and target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials are configured. urllib3 may apply these target-specific settings to the proxy TLS handshake. This may cause urllib3 to: - send SNI intended for the target server to the proxy; - verify the proxy using a hostname or certificate fingerprint intended for the target server; or - present a TLS client certificate intended for the target server to the proxy. Code connecting through a plain HTTP proxy does not establish a TLS connection to the proxy and is not affected by this issue. ##### Remediation Upgrade to urllib3 2.8.0 or later. urllib3 2.8.0 independently applies the explicitly configured `proxy_ssl_context` and proxy-specific certificate assertions to the HTTPS proxy connection. Target-specific SNI, certificate assertions, and TLS client certificate parameters are no longer applied to the HTTPS proxy handshake. For backward compatibility, when an HTTPS proxy is used with `use_forwarding_for_https=True` and `proxy_ssl_context` is not provided, urllib3 2.8.0 continues to use `ssl_context` for the TLS connection to the proxy. This configuration emits a `FutureWarning`. In urllib3 3.0, passing `ssl_context` with `use_forwarding_for_https=True` for an HTTPS proxy will raise an error. Applications should use `proxy_ssl_context` to configure TLS for an HTTPS forwarding proxy. The fixes were implemented in commits b6447295fff7b38fdffc67e0df9712d60cef3cc3 and 07408cec79d1856d81bb42c74a904a24fdb9e465. #### Severity - CVSS Score: 7.6 / 10 (High) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-8988-9cw3-xx77](https://github.com/urllib3/urllib3/security/advisories/GHSA-8988-9cw3-xx77) - [https://nvd.nist.gov/vuln/detail/CVE-2026-97687](https://nvd.nist.gov/vuln/detail/CVE-2026-97687) - [https://github.com/urllib3/urllib3/pull/5093](https://github.com/urllib3/urllib3/pull/5093) - [https://github.com/urllib3/urllib3/commit/07408cec79d1856d81bb42c74a904a24fdb9e465](https://github.com/urllib3/urllib3/commit/07408cec79d1856d81bb42c74a904a24fdb9e465) - [https://github.com/urllib3/urllib3/commit/b6447295fff7b38fdffc67e0df9712d60cef3cc3](https://github.com/urllib3/urllib3/commit/b6447295fff7b38fdffc67e0df9712d60cef3cc3) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) - [https://github.com/urllib3/urllib3/releases/tag/2.8.0](https://github.com/urllib3/urllib3/releases/tag/2.8.0) This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-8988-9cw3-xx77) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)). </details> --- ### urllib3: Chunked Deflate streaming can enter an infinite loop [CVE-2026-97688](https://nvd.nist.gov/vuln/detail/CVE-2026-97688) / [GHSA-gh4c-6fx4-qh6g](https://github.com/advisories/GHSA-gh4c-6fx4-qh6g) / PYSEC-2026-4176 <details> <summary>More information</summary> #### Details ##### Impact urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading content in chunks instead of loading the entire response body into memory at once. urllib3 can decompress response bodies according to the HTTP `Content-Encoding` header. When streaming a compressed, chunked response, urllib3 first consumes data already buffered by the decoder before reading the next HTTP chunk. However, urllib3 versions from 2.6.2 through 2.7.0 could enter an infinite loop when a chunked response contained bytes after the end of the Deflate stream. If the decompressed body exceeded the requested streaming chunk size, Python's zlib implementation could retain the trailing bytes as unconsumed input after reaching the end of the compressed stream. urllib3 would repeatedly attempt to decode those same bytes without making progress or reading more data from the network. A malicious server could exploit this behavior to cause excessive CPU usage and prevent the affected request from completing on the client. Network read timeouts would not interrupt the loop because no further socket operation was required. ##### Affected usages Applications and libraries using urllib3 versions 2.6.2 through 2.7.0 may be affected when all of the following conditions are met: 1. Compressed responses from an untrusted source are streamed using `HTTPResponse.stream(amt=N)` or `HTTPResponse.read_chunked(amt=N)` with a positive, finite chunk size. 2. Content decoding is enabled. 3. The response uses both `Transfer-Encoding: chunked` and `Content-Encoding: deflate`. 4. The decoded body exceeds the requested chunk size and the encoded body contains bytes after the end of the Deflate stream. `HTTPResponse.stream()` uses a finite chunk size by default and is therefore affected when the other conditions are met. ##### Remediation Upgrade to urllib3 2.8.0, in which the Deflate decoder stops accepting input after reaching the end of the compressed stream and no longer reports trailing bytes as data that can produce more decoded output. If upgrading is not immediately possible, disable automatic content decoding for responses from untrusted sources by setting `decode_content=False`, or reject streamed responses using the Deflate content encoding. Applications that disable automatic decoding must handle the compressed response safely at another layer. #### Severity - CVSS Score: 6.9 / 10 (Medium) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g](https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g) - [https://nvd.nist.gov/vuln/detail/CVE-2026-97688](https://nvd.nist.gov/vuln/detail/CVE-2026-97688) - [https://github.com/urllib3/urllib3/commit/ea2ad7b21a80da3632f80016526a18864586077f](https://github.com/urllib3/urllib3/commit/ea2ad7b21a80da3632f80016526a18864586077f) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) - [https://github.com/urllib3/urllib3/releases/tag/2.8.0](https://github.com/urllib3/urllib3/releases/tag/2.8.0) This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-gh4c-6fx4-qh6g) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)). </details> --- ### urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory [CVE-2026-97689](https://nvd.nist.gov/vuln/detail/CVE-2026-97689) / [GHSA-vxq7-64xx-v4gw](https://github.com/advisories/GHSA-vxq7-64xx-v4gw) / PYSEC-2026-4177 <details> <summary>More information</summary> #### Details ##### Impact urllib3's [streaming API](https://urllib3.readthedocs.io/en/2.7.0/advanced-usage.html#streaming-and-i-o) is designed for efficiently handling large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. When decoding a [chunked-transfer-encoded response](https://httpwg.org/specs/rfc9112.html#chunked.encoding), this API reads each chunk's size field by buffering until it sees `\n` or EOF. A malicious HTTP server can return `Transfer-Encoding: chunked` and then send a very long run of bytes without any newline, causing the streaming client to buffer that entire run before urllib3 can reject the chunk size as invalid and allocate more memory than intended. To fix the issue, we'll reject chunk-size fields larger than 65536 bytes, as already done in the non-streaming case, which is currently handled by the Python standard library. Note that this only applies to reading the chunk-size field, not the chunk data, which is already handled correctly. Thus, there shouldn't be any impact for non-malicious servers. ##### Affected usages Applications and libraries using urllib3 versions earlier than 2.8.0 may be affected when streaming a chunked response from untrusted sources. Specifically, this affects the [read_chunked()](https://urllib3.readthedocs.io/en/stable/reference/urllib3.response.html#urllib3.response.BaseHTTPResponse.read_chunked) and [stream()](https://urllib3.readthedocs.io/en/stable/reference/urllib3.response.html#urllib3.response.BaseHTTPResponse.stream) methods of the HTTPResponse object. This also affects requests streaming API, which uses urllib3 under the hood. ##### Remediation Upgrade to urllib3 version 2.8.0 or later, where chunk-size fields larger than 65536 will be rejected. If upgrading is not immediately possible, consider reading the response at once using the [read()](https://urllib3.readthedocs.io/en/stable/reference/urllib3.response.html#urllib3.response.BaseHTTPResponse.read) method. #### Severity - CVSS Score: 8.9 / 10 (High) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw](https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw) - [https://nvd.nist.gov/vuln/detail/CVE-2026-97689](https://nvd.nist.gov/vuln/detail/CVE-2026-97689) - [https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed](https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) - [https://github.com/urllib3/urllib3/releases/tag/2.8.0](https://github.com/urllib3/urllib3/releases/tag/2.8.0) This data is provided by [OSV](https://osv.dev/vulnerability/GHSA-vxq7-64xx-v4gw) and the [GitHub Advisory Database](https://github.com/github/advisory-database) ([CC-BY 4.0](https://github.com/github/advisory-database/blob/main/LICENSE.md)). </details> --- ### urllib3: HTTPS proxy TLS configuration may be ignored or overridden [CVE-2026-97687](https://nvd.nist.gov/vuln/detail/CVE-2026-97687) / [GHSA-8988-9cw3-xx77](https://github.com/advisories/GHSA-8988-9cw3-xx77) / PYSEC-2026-4175 <details> <summary>More information</summary> #### Details ##### Impact urllib3 supports configuring TLS independently for an HTTPS proxy and the target server. `proxy_ssl_context`, `proxy_assert_hostname`, and `proxy_assert_fingerprint` configure the TLS connection to the proxy. `ssl_context` and the other target-specific TLS parameters configure the connection to the target server. In urllib3 versions 1.26.0 through 2.7.0, these configurations were not consistently separated. Depending on the proxy mode, urllib3 could: 1. Ignore `proxy_ssl_context` and use the target server's SSL context for the TLS connection to an HTTPS forwarding proxy. 2. Override the HTTPS proxy's certificate-verification policy with the target server's certificate-verification policy. 3. Apply target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials to the TLS connection to an HTTPS forwarding proxy. In particular, configuring `cert_reqs="CERT_NONE"` for a target server could overwrite the `verify_mode` of the SSL context configured for the HTTPS proxy. This modification occurred in place and persisted on the context object, potentially disabling proxy certificate verification for later connections that reused the same context. An attacker able to intercept the connection to an HTTPS proxy may be able to impersonate the proxy when the effective proxy TLS configuration disables certificate verification or otherwise accepts the attacker's certificate. This may occur, for example, when the target server's trust or identity policy is incorrectly applied to the proxy connection. When HTTPS forwarding is enabled, an impersonated proxy can observe or modify forwarded requests and responses, potentially exposing credentials, authentication tokens, request bodies, response data, and other sensitive information. A TLS client certificate intended for the target server may also be presented to the proxy or to an attacker impersonating it. This can disclose the client's identity and provide proof of possession of the corresponding private key. The private key itself is not transmitted during the TLS handshake. In CONNECT tunneling mode, impersonating the HTTPS proxy does not by itself defeat the separate end-to-end TLS connection between the client and the target server. ##### Affected Usages Code using urllib3 versions 1.26.0 through 2.7.0 may be affected in any of the following cases. ##### 1. The target SSL context is used for an HTTPS forwarding proxy HTTPS requests are forwarded through an HTTPS proxy with `use_forwarding_for_https=True`, and `proxy_ssl_context` is configured for the proxy. urllib3 may ignore `proxy_ssl_context` and use the target server's `ssl_context` for the proxy TLS handshake. The proxy may therefore be verified using the target server's trust and certificate policy instead of the policy explicitly configured for the proxy. ##### 2. The target verification policy overrides the proxy policy An HTTPS proxy is configured with `proxy_ssl_context`, while the target server uses a different certificate-verification policy. urllib3 may apply the target server's `cert_reqs` value to the proxy SSL context. For example, setting `cert_reqs="CERT_NONE"` for the target server may also disable certificate verification for the HTTPS proxy, even when `proxy_ssl_context` was configured to require verification. This issue can affect the TLS connection to an HTTPS proxy in both forwarding and CONNECT tunneling configurations. ##### 3. A mutated proxy SSL context is reused The same SSL context is reused as `proxy_ssl_context` across multiple connections, and certificate verification is disabled for one target server. urllib3 may modify the proxy SSL context's `verify_mode` in place. Later connections that reuse the same context may therefore connect to the HTTPS proxy without certificate verification. ##### 4. Target-specific TLS identity or credentials are applied to the proxy HTTPS requests are forwarded through an HTTPS proxy with `use_forwarding_for_https=True`, and target-specific SNI, hostname assertions, certificate fingerprint assertions, or TLS client credentials are configured. urllib3 may apply these target-specific settings to the proxy TLS handshake. This may cause urllib3 to: - send SNI intended for the target server to the proxy; - verify the proxy using a hostname or certificate fingerprint intended for the target server; or - present a TLS client certificate intended for the target server to the proxy. Code connecting through a plain HTTP proxy does not establish a TLS connection to the proxy and is not affected by this issue. ##### Remediation Upgrade to urllib3 2.8.0 or later. urllib3 2.8.0 independently applies the explicitly configured `proxy_ssl_context` and proxy-specific certificate assertions to the HTTPS proxy connection. Target-specific SNI, certificate assertions, and TLS client certificate parameters are no longer applied to the HTTPS proxy handshake. For backward compatibility, when an HTTPS proxy is used with `use_forwarding_for_https=True` and `proxy_ssl_context` is not provided, urllib3 2.8.0 continues to use `ssl_context` for the TLS connection to the proxy. This configuration emits a `FutureWarning`. In urllib3 3.0, passing `ssl_context` with `use_forwarding_for_https=True` for an HTTPS proxy will raise an error. Applications should use `proxy_ssl_context` to configure TLS for an HTTPS forwarding proxy. The fixes were implemented in commits b6447295fff7b38fdffc67e0df9712d60cef3cc3 and 07408cec79d1856d81bb42c74a904a24fdb9e465. #### Severity - CVSS Score: 7.6 / 10 (High) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-8988-9cw3-xx77](https://github.com/urllib3/urllib3/security/advisories/GHSA-8988-9cw3-xx77) - [https://nvd.nist.gov/vuln/detail/CVE-2026-97687](https://nvd.nist.gov/vuln/detail/CVE-2026-97687) - [https://github.com/urllib3/urllib3/pull/5093](https://github.com/urllib3/urllib3/pull/5093) - [https://github.com/urllib3/urllib3/commit/07408cec79d1856d81bb42c74a904a24fdb9e465](https://github.com/urllib3/urllib3/commit/07408cec79d1856d81bb42c74a904a24fdb9e465) - [https://github.com/urllib3/urllib3/commit/b6447295fff7b38fdffc67e0df9712d60cef3cc3](https://github.com/urllib3/urllib3/commit/b6447295fff7b38fdffc67e0df9712d60cef3cc3) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) - [https://github.com/urllib3/urllib3/releases/tag/2.8.0](https://github.com/urllib3/urllib3/releases/tag/2.8.0) - [https://pypi.org/project/urllib3](https://pypi.org/project/urllib3) - [https://github.com/advisories/GHSA-8988-9cw3-xx77](https://github.com/advisories/GHSA-8988-9cw3-xx77) This data is provided by [OSV](https://osv.dev/vulnerability/PYSEC-2026-4175) and the [PyPI Advisory Database](https://github.com/pypa/advisory-database) ([CC-BY 4.0](https://github.com/pypa/advisory-database/blob/main/LICENSE)). </details> --- ### urllib3: Chunked Deflate streaming can enter an infinite loop [CVE-2026-97688](https://nvd.nist.gov/vuln/detail/CVE-2026-97688) / [GHSA-gh4c-6fx4-qh6g](https://github.com/advisories/GHSA-gh4c-6fx4-qh6g) / PYSEC-2026-4176 <details> <summary>More information</summary> #### Details ##### Impact urllib3's streaming API is designed for the efficient handling of large HTTP responses by reading content in chunks instead of loading the entire response body into memory at once. urllib3 can decompress response bodies according to the HTTP `Content-Encoding` header. When streaming a compressed, chunked response, urllib3 first consumes data already buffered by the decoder before reading the next HTTP chunk. However, urllib3 versions from 2.6.2 through 2.7.0 could enter an infinite loop when a chunked response contained bytes after the end of the Deflate stream. If the decompressed body exceeded the requested streaming chunk size, Python's zlib implementation could retain the trailing bytes as unconsumed input after reaching the end of the compressed stream. urllib3 would repeatedly attempt to decode those same bytes without making progress or reading more data from the network. A malicious server could exploit this behavior to cause excessive CPU usage and prevent the affected request from completing on the client. Network read timeouts would not interrupt the loop because no further socket operation was required. ##### Affected usages Applications and libraries using urllib3 versions 2.6.2 through 2.7.0 may be affected when all of the following conditions are met: 1. Compressed responses from an untrusted source are streamed using `HTTPResponse.stream(amt=N)` or `HTTPResponse.read_chunked(amt=N)` with a positive, finite chunk size. 2. Content decoding is enabled. 3. The response uses both `Transfer-Encoding: chunked` and `Content-Encoding: deflate`. 4. The decoded body exceeds the requested chunk size and the encoded body contains bytes after the end of the Deflate stream. `HTTPResponse.stream()` uses a finite chunk size by default and is therefore affected when the other conditions are met. ##### Remediation Upgrade to urllib3 2.8.0, in which the Deflate decoder stops accepting input after reaching the end of the compressed stream and no longer reports trailing bytes as data that can produce more decoded output. If upgrading is not immediately possible, disable automatic content decoding for responses from untrusted sources by setting `decode_content=False`, or reject streamed responses using the Deflate content encoding. Applications that disable automatic decoding must handle the compressed response safely at another layer. #### Severity - CVSS Score: 6.9 / 10 (Medium) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g](https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g) - [https://nvd.nist.gov/vuln/detail/CVE-2026-97688](https://nvd.nist.gov/vuln/detail/CVE-2026-97688) - [https://github.com/urllib3/urllib3/commit/ea2ad7b21a80da3632f80016526a18864586077f](https://github.com/urllib3/urllib3/commit/ea2ad7b21a80da3632f80016526a18864586077f) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) - [https://github.com/urllib3/urllib3/releases/tag/2.8.0](https://github.com/urllib3/urllib3/releases/tag/2.8.0) - [https://pypi.org/project/urllib3](https://pypi.org/project/urllib3) - [https://github.com/advisories/GHSA-gh4c-6fx4-qh6g](https://github.com/advisories/GHSA-gh4c-6fx4-qh6g) This data is provided by [OSV](https://osv.dev/vulnerability/PYSEC-2026-4176) and the [PyPI Advisory Database](https://github.com/pypa/advisory-database) ([CC-BY 4.0](https://github.com/pypa/advisory-database/blob/main/LICENSE)). </details> --- ### urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory [CVE-2026-97689](https://nvd.nist.gov/vuln/detail/CVE-2026-97689) / [GHSA-vxq7-64xx-v4gw](https://github.com/advisories/GHSA-vxq7-64xx-v4gw) / PYSEC-2026-4177 <details> <summary>More information</summary> #### Details ##### Impact urllib3's [streaming API](https://urllib3.readthedocs.io/en/2.7.0/advanced-usage.html#streaming-and-i-o) is designed for efficiently handling large HTTP responses by reading the content in chunks, rather than loading the entire response body into memory at once. When decoding a [chunked-transfer-encoded response](https://httpwg.org/specs/rfc9112.html#chunked.encoding), this API reads each chunk's size field by buffering until it sees `\n` or EOF. A malicious HTTP server can return `Transfer-Encoding: chunked` and then send a very long run of bytes without any newline, causing the streaming client to buffer that entire run before urllib3 can reject the chunk size as invalid and allocate more memory than intended. To fix the issue, we'll reject chunk-size fields larger than 65536 bytes, as already done in the non-streaming case, which is currently handled by the Python standard library. Note that this only applies to reading the chunk-size field, not the chunk data, which is already handled correctly. Thus, there shouldn't be any impact for non-malicious servers. ##### Affected usages Applications and libraries using urllib3 versions earlier than 2.8.0 may be affected when streaming a chunked response from untrusted sources. Specifically, this affects the [read_chunked()](https://urllib3.readthedocs.io/en/stable/reference/urllib3.response.html#urllib3.response.BaseHTTPResponse.read_chunked) and [stream()](https://urllib3.readthedocs.io/en/stable/reference/urllib3.response.html#urllib3.response.BaseHTTPResponse.stream) methods of the HTTPResponse object. This also affects requests streaming API, which uses urllib3 under the hood. ##### Remediation Upgrade to urllib3 version 2.8.0 or later, where chunk-size fields larger than 65536 will be rejected. If upgrading is not immediately possible, consider reading the response at once using the [read()](https://urllib3.readthedocs.io/en/stable/reference/urllib3.response.html#urllib3.response.BaseHTTPResponse.read) method. #### Severity - CVSS Score: 8.9 / 10 (High) - Vector String: `CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:H` #### References - [https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw](https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw) - [https://nvd.nist.gov/vuln/detail/CVE-2026-97689](https://nvd.nist.gov/vuln/detail/CVE-2026-97689) - [https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed](https://github.com/urllib3/urllib3/commit/cd770b059b543be29298ea5c52afb0b1b090f5ed) - [https://github.com/urllib3/urllib3](https://github.com/urllib3/urllib3) - [https://github.com/urllib3/urllib3/releases/tag/2.8.0](https://github.com/urllib3/urllib3/releases/tag/2.8.0) - [https://pypi.org/project/urllib3](https://pypi.org/project/urllib3) - [https://github.com/advisories/GHSA-vxq7-64xx-v4gw](https://github.com/advisories/GHSA-vxq7-64xx-v4gw) This data is provided by [OSV](https://osv.dev/vulnerability/PYSEC-2026-4177) and the [PyPI Advisory Database](https://github.com/pypa/advisory-database) ([CC-BY 4.0](https://github.com/pypa/advisory-database/blob/main/LICENSE)). </details> --- ### Release Notes <details> <summary>urllib3/urllib3 (urllib3)</summary> ### [`v2.8.0`](https://github.com/urllib3/urllib3/blob/HEAD/CHANGES.rst#280-2026-09-15) [Compare Source](https://github.com/urllib3/urllib3/compare/2.7.0...2.8.0) \================== ## Security Fixed the following security issues: - The TLS configuration for HTTPS proxies could be ignored or overridden. (High severity, `GHSA-8988-9cw3-xx77 <https://github.com/urllib3/urllib3/security/advisories/GHSA-8988-9cw3-xx77>`\_\_) - `HTTPResponse.stream()` and `read_chunked()` could buffer a chunk-size line of unbounded length in memory. (High severity, `GHSA-vxq7-64xx-v4gw <https://github.com/urllib3/urllib3/security/advisories/GHSA-vxq7-64xx-v4gw>`\_\_) - Chunked Deflate streaming could enter an infinite loop. (Medium severity, `GHSA-gh4c-6fx4-qh6g <https://github.com/urllib3/urllib3/security/advisories/GHSA-gh4c-6fx4-qh6g>`\_\_) .. caution:: ``` urllib3 2.8.0 fixes HTTPS proxy TLS configuration being ignored or overridden by destination settings. Configurations relying on that behavior may require changes. Configure proxy CA certificates and client certificates in ``proxy_ssl_context``, and proxy identity checks with ``proxy_assert_hostname`` or ``proxy_assert_fingerprint``. Destination client certificates and identity overrides no longer apply to HTTPS forwarding proxy connections. ``` ## Deprecations & Removals - Deprecated using an empty collection as the `Retry` option `allowed_methods` to retry any verb. (`#5044 <https://github.com/urllib3/urllib3/issues/5044>`\_\_) ## Features - Added `Url.auth_decoded` and `Url.auth_decoded_joined` convenience properties to the result of `parse_url()`. (`#4945 <https://github.com/urllib3/urllib3/issues/4945>`\_\_) - Added `basic_auth_encoding` and `proxy_basic_auth_encoding` parameters to `urllib3.util.make_headers()`. (`#5092 <https://github.com/urllib3/urllib3/issues/5092>`\_\_) ## Bugfixes - Fixed response header handling to replace obsolete folded header lines (`obs-fold`) with spaces in accordance with RFC 9112, preventing raw CRLF sequences from appearing in header values such as `Set-Cookie`. (`#1362 <https://github.com/urllib3/urllib3/issues/1362>`\_\_) - Fixed usage of `proxy_ssl_context` with `ProxyManager` when `use_forwarding_for_https=True`. Passing `ssl_context` instead of `proxy_ssl_context` for HTTPS proxies in this configuration now emits a `FutureWarning` and will raise an error in v3.0. (`#2577 <https://github.com/urllib3/urllib3/issues/2577>`\_\_) - Changed behavior of the default `ConnectionPool.pool` initialization. `LifoQueue` is now resolved from the `queue` module after the `ConnectionPool` is instantiated instead of using the default cached `QueueCls` class property. This is done because sometimes the `queue.LifoQueue` is monkey-patched late in the program, such as by gevent. (`#3289 <https://github.com/urllib3/urllib3/issues/3289>`\_\_) - Raised `UnrewindableBodyError` instead of `ValueError` when retrying a request whose body had `tell()` but not `seek()`. (`#3779 <https://github.com/urllib3/urllib3/issues/3779>`\_\_) - Decoded percent-encoded SOCKS proxy credentials before authenticating with the proxy server. (`#3785 <https://github.com/urllib3/urllib3/issues/3785>`\_\_) - Fixed `HTTPResponse.drain_conn()` to discard unread response data in 64 KiB chunks (same as the default `amt` when doing `HTTPResponse.stream(...)`). (`#5019 <https://github.com/urllib3/urllib3/issues/5019>`\_\_) - Fixed `is_ipaddress()` to detect non-standard IPv4 forms accepted by `socket.connect`, such as hex (`0x7f000001`), octal (`0177.0.0.1`), and decimal integers (`2130706433`), ensuring SSL certificate verification uses the correct mode for these addresses. (`#5029 <https://github.com/urllib3/urllib3/issues/5029>`\_\_) - Fixed `HTTPConnectionPool.urlopen` raising a misleading `FullPoolError` instead of `ValueError` when called with an invalid `timeout` argument on a pool created with `block=True`. (`#5059 <https://github.com/urllib3/urllib3/issues/5059>`\_\_) - Fixed port-zero handling to preserve explicit `:0` values instead of substituting the default ports 80 or 443 in URL parsing, pool selection, proxy configuration, `connection_from_url()`, and HTTP/2 request authority. (`#5071 <https://github.com/urllib3/urllib3/issues/5071>`**, `#5101 <https://github.com/urllib3/urllib3/issues/5101>`**) - Fixed a bug where `PoolManager` passed the `assert_hostname` and `assert_fingerprint` parameters to HTTP connection pools. (`#5077 <https://github.com/urllib3/urllib3/issues/5077>`\_\_) - Fixed `HTTPConnectionPool.urlopen()` and HTTP proxy forwarding to strip URL fragments from absolute request targets before sending requests. (`#5079 <https://github.com/urllib3/urllib3/issues/5079>`\_\_) - Added safeguards to the proxy tunneling code to prevent potential security issues when handling invalid characters in the proxy host and HTTP headers. This change affects users of Python 3.10, Python 3.11, and Python 3.12 when the standard library does not contain the fix; those on newer Python versions should upgrade to 3.13.14+ or 3.14.5+ to get the same security fixes. (`#5091 <https://github.com/urllib3/urllib3/issues/5091>`\_\_) - Fixed `HTTPSConnection.connect()` overriding `ProxyConfig.ssl_context`'s certificate policy and proxy identity checks with the target connection's TLS settings when forwarding through an HTTPS proxy. `HTTPSConnection` no longer applies target SNI, assertions, or client credentials to forwarding proxy handshakes and continues to use its `ssl_context` as a fallback when an HTTPS proxy forwards an HTTP target. (`#5093 <https://github.com/urllib3/urllib3/issues/5093>`\_\_) - Fixed URL parsing to more strictly enforce RFC 3986 host syntax, rejecting invalid host input such as raw spaces and control characters, malformed percent-encodings, and percent-encoded control characters in HTTP(S) hosts and IPv6 zone identifiers, including proxy CONNECT tunnel targets. Host normalization now also follows RFC 3986 normalization rules for percent-encoded octets by decoding percent-encoded unreserved characters and uppercasing the hexadecimal digits of retained percent-encoded octets. (`#5095 <https://github.com/urllib3/urllib3/issues/5095>`\_\_) - Fixed an `AttributeError` on Python built with OpenSSL 4+, where `ssl.PROTOCOL_TLSv1` no longer exists. (`#5097 <https://github.com/urllib3/urllib3/issues/5097>`\_\_) - Fixed `urllib3.contrib.pyopenssl` to use cryptography APIs when reading a certificate subject and loading encrypted private keys, avoiding `DeprecationWarning` raised by pyOpenSSL 26.3.0+. (`#5103 <https://github.com/urllib3/urllib3/issues/5103>`\_\_) - Fixed handling of HTTP 303 redirects for requests with chunked or file-like bodies. (`#5161 <https://github.com/urllib3/urllib3/issues/5161>`\_\_) - Fixed `assert_fingerprint()` to raise `SSLError` instead of `binascii.Error` when a fingerprint has a supported length but contains non-hexadecimal characters. (`#5211 <https://github.com/urllib3/urllib3/issues/5211>`\_\_) ## Misc - Added a `test` dependency group containing the minimum dependencies needed to run the test suite, intended for downstream packagers. The `dev-base` and `mypy` groups now include this new group via `include-group`, removing duplication. (`#3594 <https://github.com/urllib3/urllib3/issues/3594>`\_\_) - Fixed test failures with pytest >= 9.1. (`#5094 <https://github.com/urllib3/urllib3/issues/5094>`\_\_) - Enabled JSPI tests with Firefox in the Emscripten test suite. (`#5166 <https://github.com/urllib3/urllib3/issues/5166>`\_\_) - Improved streamed response decoding performance. (`#5209 <https://github.com/urllib3/urllib3/issues/5209>`\_\_) - Fixed flaky tests. (`#5232 <https://github.com/urllib3/urllib3/issues/5232>`**, `#5234 <https://github.com/urllib3/urllib3/issues/5234>`**, `#5239 <https://github.com/urllib3/urllib3/issues/5239>`\_\_) ### [`v2.7.0`](https://github.com/urllib3/urllib3/blob/HEAD/CHANGES.rst#270-2026-05-07) [Compare Source](https://github.com/urllib3/urllib3/compare/2.6.3...2.7.0) \======================= ## Security Addressed high-severity security issues. Impact was limited to specific use cases detailed in the accompanying advisories; overall user exposure was estimated to be marginal. - Decompression-bomb safeguards of the streaming API were bypassed: 1. When `HTTPResponse.drain_conn()` was called after the response had been read and decompressed partially. 2. During the second `HTTPResponse.read(amt=N)` or `HTTPResponse.stream(amt=N)` call when the response was decompressed using the official `Brotli <https://pypi.org/project/brotli/>`\_\_ library. See `GHSA-mf9v-mfxr-j63j <https://github.com/urllib3/urllib3/security/advisories/GHSA-mf9v-mfxr-j63j>`\_\_ for details. - HTTP pools created using `ProxyManager.connection_from_url` did not strip sensitive headers specified in `Retry.remove_headers_on_redirect` when redirecting to a different host. (`GHSA-qccp-gfcp-xxvc <https://github.com/urllib3/urllib3/security/advisories/GHSA-qccp-gfcp-xxvc>`\_\_) ## Deprecations and Removals - Used `FutureWarning` instead of `DeprecationWarning` for better visibility of existing deprecation notices. Rescheduled the removal of deprecated features to version 3.0. (`#3763 <https://github.com/urllib3/urllib3/issues/3763>`\_\_) - Removed support for end-of-life Python 3.9. (`#3720 <https://github.com/urllib3/urllib3/issues/3720>`\_\_) - Removed support for end-of-life PyPy3.10. (`#4979 <https://github.com/urllib3/urllib3/issues/4979>`\_\_) - Bumped the minimum supported pyOpenSSL version to 19.0.0. (`#3777 <https://github.com/urllib3/urllib3/issues/3777>`\_\_) ## Bugfixes - Fixed a bug where `HTTPResponse.read(amt=None)` was ignoring decompressed data buffered from previous partial reads. (`#3636 <https://github.com/urllib3/urllib3/issues/3636>`\_\_) - Fixed a bug where `HTTPResponse.read()` could cache only part of the response after a partial read when `cache_content=True`. (`#4967 <https://github.com/urllib3/urllib3/issues/4967>`\_\_) - Fixed `HTTPResponse.stream()` and `HTTPResponse.read_chunked()` to handle `amt=0`. (`#3793 <https://github.com/urllib3/urllib3/issues/3793>`\_\_) - Updated `_TYPE_BODY` type alias to include missing `Iterable[str]`, matching the documented and runtime behavior of chunked request bodies. (`#3798 <https://github.com/urllib3/urllib3/issues/3798>`\_\_) - Fixed `LocationParseError` when paths resembling schemeless URIs were passed to `HTTPConnectionPool.urlopen()`. (`#3352 <https://github.com/urllib3/urllib3/issues/3352>`\_\_) - Fixed `BaseHTTPResponse.readinto()` type annotation to accept `memoryview` in addition to `bytearray`, matching the `io.RawIOBase.readinto` contract and enabling use with `io.BufferedReader` without type errors. (`#3764 <https://github.com/urllib3/urllib3/issues/3764>`\_\_) </details> --- ### Configuration 📅 **Schedule**: (UTC) - Branch creation - At any time (no schedule defined) - Automerge - At any time (no schedule defined) 🚦 **Automerge**: Disabled by config. Please merge this manually once you are satisfied. ♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the rebase/retry checkbox. 🔕 **Ignore**: Close this PR and you won't be reminded about this update again. --- - [ ] If you want to rebase/retry this PR, check this box --- This PR has been generated by [Mend Renovate CLI](https://github.com/renovatebot/renovate).

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chore(deps): update dependency urllib3 to v2.8.0 [security]

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chore(deps): update dependency urllib3 to v2.8.0 [security] #83

urllib3: Decompression-bomb safeguards bypassed in parts of the streaming API

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Impact

Affected usages

Remediation

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urllib3: Sensitive headers forwarded across origins in proxied low-level redirects

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Impact

Affected usage

Remediation

Severity

References

CVE-2026-44431 / GHSA-qccp-gfcp-xxvc / PYSEC-2026-141

Details

Severity

References

CVE-2026-44432 / GHSA-mf9v-mfxr-j63j / PYSEC-2026-142

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Severity

References

urllib3: HTTPS proxy TLS configuration may be ignored or overridden

Details

Impact

Affected Usages

1. The target SSL context is used for an HTTPS forwarding proxy

2. The target verification policy overrides the proxy policy

3. A mutated proxy SSL context is reused

4. Target-specific TLS identity or credentials are applied to the proxy

Remediation

Severity

References

urllib3: Chunked Deflate streaming can enter an infinite loop

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Affected usages

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urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory

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Impact

Affected usages

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Severity

References

urllib3: HTTPS proxy TLS configuration may be ignored or overridden

Details

Impact

Affected Usages

1. The target SSL context is used for an HTTPS forwarding proxy

2. The target verification policy overrides the proxy policy

3. A mutated proxy SSL context is reused

4. Target-specific TLS identity or credentials are applied to the proxy

Remediation

Severity

References

urllib3: Chunked Deflate streaming can enter an infinite loop

Details

Impact

Affected usages

Remediation

Severity

References

urllib3: HTTPResponse.stream()/read_chunked() buffers an unbounded chunk-size line into memory

Details

Impact

Affected usages

Remediation

Severity

References

Release Notes

v2.8.0

Security

Deprecations & Removals

Features

Bugfixes

`v2.8.0`

`v2.7.0`