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CVE-2025-66418

CVE-2025-66418 · urllib3 allows an unbounded number of links in the decompression chain

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 1.24 and prior to 2.6.0, the number of links in the decompression chain was unbounded allowing a malicious server to insert a virtually unlimited number of compression steps leading to high CPU usage and massive memory allocation for the decompressed data. This vulnerability is fixed in 2.6.0.

CVSS 8.9 · High · EPSS 0.7% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • urllib3

    Versions
    • >= 1.24, < 2.6.0: Affected

    No fix published

  • python-urllib3 Debian:12

    Versions
    • 1.26.12-1
    • 1.26.12-1+deb12u1
    Affected ranges
    • ECOSYSTEM: < 1.26.12-1+deb12u2

    Update to 1.26.12-1+deb12u2

  • python-urllib3 Debian:13

    Versions
    • 2.3.0-3
    Affected ranges
    • ECOSYSTEM: < 2.3.0-3+deb13u1

    Update to 2.3.0-3+deb13u1

  • python-urllib3 Debian:14

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

    Update to 2.5.0-1.1

  • urllib3 PyPI

    Versions
    • 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
    • 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: ≥ 1.24, < 2.6.0

    Update to 2.6.0

  • 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
    Affected ranges
    • ECOSYSTEM: < 1.25.8-2ubuntu0.4+esm2

    Update to 1.25.8-2ubuntu0.4+esm2

  • 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
    Affected ranges
    • ECOSYSTEM: < 1.26.5-1~exp1ubuntu0.4

    Update to 1.26.5-1~exp1ubuntu0.4

  • 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
    Affected ranges
    • ECOSYSTEM: < 22.0.2+dfsg-1ubuntu0.7+esm1

    Update to 22.0.2+dfsg-1ubuntu0.7+esm1

  • 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
    Affected ranges
    • ECOSYSTEM: < 24.0+dfsg-1ubuntu1.3+esm1

    Update to 24.0+dfsg-1ubuntu1.3+esm1

  • 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

Original sources

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