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chore(deps): update dependency urllib3 to v2.7.0 [security]#9179

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bshaffer merged 1 commit into
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renovate-bot:renovate/pypi-urllib3-vulnerability
May 11, 2026
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chore(deps): update dependency urllib3 to v2.7.0 [security]#9179
bshaffer merged 1 commit into
googleapis:mainfrom
renovate-bot:renovate/pypi-urllib3-vulnerability

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This PR contains the following updates:

Package Change Age Confidence
urllib3 (changelog) ==2.6.3==2.7.0 age confidence

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

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

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:

  1. During the second HTTPResponse.read(amt=N) call when the response was decompressed using the official 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 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 to 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

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


Release Notes

urllib3/urllib3 (urllib3)

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.
    (#&#8203;3763 <https://github.com/urllib3/urllib3/issues/3763>__)
  • Removed support for end-of-life Python 3.9.
    (#&#8203;3720 <https://github.com/urllib3/urllib3/issues/3720>__)
  • Removed support for end-of-life PyPy3.10.
    (#&#8203;4979 <https://github.com/urllib3/urllib3/issues/4979>__)
  • Bumped the minimum supported pyOpenSSL version to 19.0.0.
    (#&#8203;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.
    (#&#8203;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.
    (#&#8203;4967 <https://github.com/urllib3/urllib3/issues/4967>__)
  • Fixed HTTPResponse.stream() and HTTPResponse.read_chunked() to handle
    amt=0.
    (#&#8203;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.
    (#&#8203;3798 <https://github.com/urllib3/urllib3/issues/3798>__)
  • Fixed LocationParseError when paths resembling schemeless URIs were
    passed to HTTPConnectionPool.urlopen().
    (#&#8203;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.
    (#&#8203;3764 <https://github.com/urllib3/urllib3/issues/3764>__)

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This PR was generated by Mend Renovate. View the repository job log.

@renovate-bot renovate-bot requested a review from a team as a code owner May 11, 2026 15:54
@trusted-contributions-gcf trusted-contributions-gcf Bot added the owlbot:run Add this label to trigger the Owlbot post processor. label May 11, 2026
@gcf-owl-bot gcf-owl-bot Bot removed the owlbot:run Add this label to trigger the Owlbot post processor. label May 11, 2026
@bshaffer bshaffer merged commit 9677cd6 into googleapis:main May 11, 2026
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@renovate-bot renovate-bot deleted the renovate/pypi-urllib3-vulnerability branch May 11, 2026 18:40
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