p PatchFirst

CVE-2025-66471

CVE-2025-66471 · urllib3 Streaming API improperly handles highly compressed data

This page contains facts from public vulnerability sources. Check the original advisory before updating.

urllib3 is a user-friendly HTTP client library for Python. Starting in version 1.0 and prior to 2.6.0, the Streaming API improperly handles highly compressed data. 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. When streaming a compressed response, urllib3 can perform decoding or decompression based on the HTTP Content-Encoding header (e.g., gzip, deflate, br, or zstd). The library must read compressed data from the network and decompress it until the requested chunk size is met. Any resulting decompressed data that exceeds the requested amount is held in an internal buffer for the next read operation. The decompression logic could cause urllib3 to fully decode a small amount of highly compressed data in a single operation. This can result in excessive resource consumption (high CPU usage and massive memory allocation for the decompressed data.

CVSS 8.9 · High · EPSS 0.7% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • urllib3

    Versions
    • >= 1.0, < 2.6.0: Affected

    No fix published

  • python-urllib3 Debian:12

    Versions
    • 1.26.12-1
    • 1.26.12-1+deb12u1
    • 1.26.12-1+deb12u2
    • 1.26.12-1+deb12u3
    • 1.26.12-1+deb12u4
    • 1.26.16-1
    • 1.26.17-1
    • 1.26.18-1
    • 1.26.18-2
    • 2.0.7-1
    • 2.0.7-2
    • 2.2.3-1
    • 2.2.3-2
    • 2.2.3-3
    • 2.2.3-4
    • 2.3.0-1
    • 2.3.0-2
    • 2.3.0-3
    • 2.5.0-1
    • 2.5.0-1.1
    • 2.5.0-2
    • 2.6.3-1
    • 2.6.3-2
    • 2.7.0-1
    • 2.7.0-2
    • 2.7.0-3
    • 2.8.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Debian:13

    Versions
    • 2.3.0-3
    • 2.3.0-3+deb13u1
    • 2.3.0-3+deb13u2
    • 2.5.0-1
    • 2.5.0-1.1
    • 2.5.0-2
    • 2.6.3-1
    • 2.6.3-2
    • 2.7.0-1
    • 2.7.0-2
    • 2.7.0-3
    • 2.8.0-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Debian:14

    Versions
    • 2.3.0-3
    • 2.5.0-1
    • 2.5.0-1.1
    • 2.5.0-2
    Affected ranges
    • ECOSYSTEM: < 2.6.3-1

    Update to 2.6.3-1

  • urllib3 PyPI

    Versions
    • 1.0
    • 1.0.1
    • 1.0.2
    • 1.1
    • 1.10
    • 1.10.1
    • 1.10.2
    • 1.10.3
    • 1.10.4
    • 1.11
    • 1.12
    • 1.13
    • 1.13.1
    • 1.14
    • 1.15
    • 1.15.1
    • 1.16
    • 1.17
    • 1.18
    • 1.18.1
    • 1.19
    • 1.19.1
    • 1.2
    • 1.2.1
    • 1.2.2
    • 1.20
    • 1.21
    • 1.21.1
    • 1.22
    • 1.23
    • 1.24
    • 1.24.1
    • 1.24.2
    • 1.24.3
    • 1.25
    • 1.25.1
    • 1.25.10
    • 1.25.11
    • 1.25.2
    • 1.25.3
    • 1.25.4
    • 1.25.5
    • 1.25.6
    • 1.25.7
    • 1.25.8
    • 1.25.9
    • 1.26.0
    • 1.26.1
    • 1.26.10
    • 1.26.11
    • 1.26.12
    • 1.26.13
    • 1.26.14
    • 1.26.15
    • 1.26.16
    • 1.26.17
    • 1.26.18
    • 1.26.19
    • 1.26.2
    • 1.26.20
    • 1.26.3
    • 1.26.4
    • 1.26.5
    • 1.26.6
    • 1.26.7
    • 1.26.8
    • 1.26.9
    • 1.3
    • 1.4
    • 1.5
    • 1.6
    • 1.7
    • 1.7.1
    • 1.8
    • 1.8.2
    • 1.8.3
    • 1.9
    • 1.9.1
    • 2.0.0
    • 2.0.0a1
    • 2.0.0a2
    • 2.0.0a3
    • 2.0.0a4
    • 2.0.1
    • 2.0.2
    • 2.0.3
    • 2.0.4
    • 2.0.5
    • 2.0.6
    • 2.0.7
    • 2.1.0
    • 2.2.0
    • 2.2.1
    • 2.2.2
    • 2.2.3
    • 2.3.0
    • 2.4.0
    • 2.5.0
    Affected ranges
    • ECOSYSTEM: ≥ 1.0, < 2.6.0

    Update to 2.6.0

  • python-pip Ubuntu:Pro:14.04:LTS

    Versions
    • 1.4.1-2
    • 1.5.4-1
    • 1.5.4-1ubuntu1
    • 1.5.4-1ubuntu3
    • 1.5.4-1ubuntu4
    • 1.5.4-1ubuntu4+esm1
    • 1.5.4-1ubuntu4+esm2
    • 1.5.4-1ubuntu4+esm3
    • 1.5.4-1ubuntu4+esm4
    • 1.5.4-1ubuntu4+esm5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Ubuntu:Pro:14.04:LTS

    Versions
    • 1.6-2
    • 1.7.1-1
    • 1.7.1-1build1
    • 1.7.1-1ubuntu0.1
    • 1.7.1-1ubuntu3
    • 1.7.1-1ubuntu4
    • 1.7.1-1ubuntu4.1
    • 1.7.1-1ubuntu4.1+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Ubuntu:Pro:16.04:LTS

    Versions
    • 1.11-1
    • 1.12-1
    • 1.13.1-1
    • 1.13.1-2
    • 1.13.1-2ubuntu0.16.04.1
    • 1.13.1-2ubuntu0.16.04.2
    • 1.13.1-2ubuntu0.16.04.3
    • 1.13.1-2ubuntu0.16.04.4
    • 1.13.1-2ubuntu0.16.04.4+esm1
    • 1.13.1-2ubuntu0.16.04.4+esm2
    • 1.13.1-2ubuntu0.16.04.4+esm3
    • 1.13.1-2ubuntu0.16.04.4+esm4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-pip Ubuntu:Pro:16.04:LTS

    Versions
    • 1.5.6-7ubuntu1
    • 1.5.6-7ubuntu2
    • 8.0.2-7
    • 8.0.3-1
    • 8.0.3-2
    • 8.1.0-1
    • 8.1.0-2
    • 8.1.1-1
    • 8.1.1-2
    • 8.1.1-2ubuntu0.1
    • 8.1.1-2ubuntu0.2
    • 8.1.1-2ubuntu0.4
    • 8.1.1-2ubuntu0.6
    • 8.1.1-2ubuntu0.6+esm2
    • 8.1.1-2ubuntu0.6+esm3
    • 8.1.1-2ubuntu0.6+esm4
    • 8.1.1-2ubuntu0.6+esm5
    • 8.1.1-2ubuntu0.6+esm6
    • 8.1.1-2ubuntu0.6+esm8
    • 8.1.1-2ubuntu0.6+esm10
    • 8.1.1-2ubuntu0.6+esm11
    • 8.1.1-2ubuntu0.6+esm12
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Ubuntu:Pro:18.04:LTS

    Versions
    • 1.21.1-1
    • 1.22-1
    • 1.22-1ubuntu0.18.04.1
    • 1.22-1ubuntu0.18.04.2
    • 1.22-1ubuntu0.18.04.2+esm1
    • 1.22-1ubuntu0.18.04.2+esm2
    • 1.22-1ubuntu0.18.04.2+esm3
    • 1.22-1ubuntu0.18.04.2+esm4
    • 1.22-1ubuntu0.18.04.2+esm5
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-pip Ubuntu:Pro:18.04:LTS

    Versions
    • 9.0.1-2
    • 9.0.1-2.3~ubuntu1
    • 9.0.1-2.3~ubuntu1.18.04.1
    • 9.0.1-2.3~ubuntu1.18.04.2
    • 9.0.1-2.3~ubuntu1.18.04.3
    • 9.0.1-2.3~ubuntu1.18.04.4
    • 9.0.1-2.3~ubuntu1.18.04.5
    • 9.0.1-2.3~ubuntu1.18.04.5+esm2
    • 9.0.1-2.3~ubuntu1.18.04.5+esm3
    • 9.0.1-2.3~ubuntu1.18.04.6
    • 9.0.1-2.3~ubuntu1.18.04.6+esm1
    • 9.0.1-2.3~ubuntu1.18.04.7
    • 9.0.1-2.3~ubuntu1.18.04.7+esm1
    • 9.0.1-2.3~ubuntu1.18.04.8
    • 9.0.1-2.3~ubuntu1.18.04.8+esm1
    • 9.0.1-2.3~ubuntu1.18.04.8+esm2
    • 9.0.1-2.3~ubuntu1.18.04.8+esm4
    • 9.0.1-2.3~ubuntu1.18.04.8+esm6
    • 9.0.1-2.3~ubuntu1.18.04.8+esm7
    • 9.0.1-2.3~ubuntu1.18.04.8+esm8
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Ubuntu:Pro:20.04:LTS

    Versions
    • 1.24.1-1ubuntu1
    • 1.24.1-1ubuntu2
    • 1.25.8-1
    • 1.25.8-2
    • 1.25.8-2ubuntu0.1
    • 1.25.8-2ubuntu0.2
    • 1.25.8-2ubuntu0.3
    • 1.25.8-2ubuntu0.4
    • 1.25.8-2ubuntu0.4+esm1
    • 1.25.8-2ubuntu0.4+esm2
    • 1.25.8-2ubuntu0.4+esm3
    • 1.25.8-2ubuntu0.4+esm4
    • 1.25.8-2ubuntu0.4+esm5
    • 1.25.8-2ubuntu0.4+esm6
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-pip Ubuntu:Pro:20.04:LTS

    Versions
    • 18.1-5
    • 18.1-5build1
    • 18.1-5ubuntu1
    • 20.0.2-2
    • 20.0.2-4
    • 20.0.2-5
    • 20.0.2-5ubuntu1
    • 20.0.2-5ubuntu1.1
    • 20.0.2-5ubuntu1.3
    • 20.0.2-5ubuntu1.4
    • 20.0.2-5ubuntu1.5
    • 20.0.2-5ubuntu1.6
    • 20.0.2-5ubuntu1.7
    • 20.0.2-5ubuntu1.8
    • 20.0.2-5ubuntu1.9
    • 20.0.2-5ubuntu1.10
    • 20.0.2-5ubuntu1.10+esm2
    • 20.0.2-5ubuntu1.11
    • 20.0.2-5ubuntu1.11+esm2
    • 20.0.2-5ubuntu1.11+esm3
    • 20.0.2-5ubuntu1.11+esm4
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Ubuntu:22.04:LTS

    Versions
    • 1.26.5-1~exp1
    • 1.26.5-1~exp1ubuntu0.1
    • 1.26.5-1~exp1ubuntu0.2
    • 1.26.5-1~exp1ubuntu0.3
    • 1.26.5-1~exp1ubuntu0.4
    • 1.26.5-1~exp1ubuntu0.5
    • 1.26.5-1~exp1ubuntu0.6
    • 1.26.5-1~exp1ubuntu0.7
    • 1.26.5-1~exp1ubuntu0.8
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-pip Ubuntu:Pro:22.04:LTS

    Versions
    • 20.3.4-4
    • 21.3.1+dfsg-3
    • 22.0.2+dfsg-1
    • 22.0.2+dfsg-1ubuntu0.1
    • 22.0.2+dfsg-1ubuntu0.2
    • 22.0.2+dfsg-1ubuntu0.3
    • 22.0.2+dfsg-1ubuntu0.4
    • 22.0.2+dfsg-1ubuntu0.5
    • 22.0.2+dfsg-1ubuntu0.6
    • 22.0.2+dfsg-1ubuntu0.7
    • 22.0.2+dfsg-1ubuntu0.7+esm1
    • 22.0.2+dfsg-1ubuntu0.7+esm2
    Affected ranges
    • ECOSYSTEM: < 22.0.2+dfsg-1ubuntu0.7+esm3

    Update to 22.0.2+dfsg-1ubuntu0.7+esm3

  • python-urllib3 Ubuntu:24.04:LTS

    Versions
    • 1.26.16-1
    • 1.26.18-1
    • 2.0.7-1
    • 2.0.7-1ubuntu0.1
    • 2.0.7-1ubuntu0.2
    Affected ranges
    • ECOSYSTEM: < 2.0.7-1ubuntu0.3

    Update to 2.0.7-1ubuntu0.3

  • python-pip Ubuntu:Pro:24.04:LTS

    Versions
    • 23.2+dfsg-1
    • 23.3+dfsg-1
    • 24.0+dfsg-1
    • 24.0+dfsg-1ubuntu1
    • 24.0+dfsg-1ubuntu1.1
    • 24.0+dfsg-1ubuntu1.2
    • 24.0+dfsg-1ubuntu1.3
    • 24.0+dfsg-1ubuntu1.3+esm1
    • 24.0+dfsg-1ubuntu1.3+esm2
    Affected ranges
    • ECOSYSTEM: < 24.0+dfsg-1ubuntu1.3+esm3

    Update to 24.0+dfsg-1ubuntu1.3+esm3

  • python-pip Ubuntu:25.10

    Versions
    • 25.0+dfsg-1
    • 25.1.1+dfsg-1
    • 25.1.1+dfsg-1ubuntu1
    • 25.1.1+dfsg-1ubuntu2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Ubuntu:25.10

    Versions
    • 2.3.0-2
    • 2.3.0-2ubuntu1
    • 2.3.0-3
    Affected ranges
    • ECOSYSTEM: < 2.3.0-3ubuntu0.1

    Update to 2.3.0-3ubuntu0.1

  • python-pip Ubuntu:26.10

    Versions
    • 25.1.1+dfsg-1ubuntu2
    • 26.1.2+dfsg-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-urllib3 Ubuntu:26.04:LTS

    Versions
    • 2.3.0-3
    • 2.5.0-1
    Affected ranges
    • ECOSYSTEM: < 2.5.0-1ubuntu1

    Update to 2.5.0-1ubuntu1

  • python-pip Ubuntu:Pro:26.04:LTS

    Versions
    • 25.1.1+dfsg-1ubuntu2
    • 25.1.1+dfsg-1ubuntu2+esm1
    • 25.1.1+dfsg-1ubuntu2+esm2
    Affected ranges
    • ECOSYSTEM: < 25.1.1+dfsg-1ubuntu2+esm3

    Update to 25.1.1+dfsg-1ubuntu2+esm3

Original sources

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