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CVE-2026-102598

CVE-2026-102598 · Werkzeug safe_join() allows Windows special device names

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

Werkzeug is a comprehensive WSGI web application library. Prior to 3.1.9, the safe_join function used by send_from_directory can allow a NUL: special-device path because safe_join checks the Windows device name without first removing an empty NTFS ADS marker. The trigger is that an application runs on Windows with NTFS and serves a user-specified path ending in a special device name such as NUL:. The attack mechanism is that a requested path ends in a Windows special device name with an empty ADS marker. The impact is that the special device opens successfully and the file read hangs indefinitely. This issue is fixed in version 3.1.9.

CVSS 6.3 · Medium · EPSS 0.4% · Fix available

Published
Updated

Stack: system · python

Affected products and versions

  • werkzeug

    Versions
    • < 3.1.9: Affected

    No fix published

  • werkzeug PyPI

    Versions
    • 0.1
    • 0.10
    • 0.10.1
    • 0.10.2
    • 0.10.3
    • 0.10.4
    • 0.11
    • 0.11.1
    • 0.11.10
    • 0.11.11
    • 0.11.12
    • 0.11.13
    • 0.11.14
    • 0.11.15
    • 0.11.2
    • 0.11.3
    • 0.11.4
    • 0.11.5
    • 0.11.6
    • 0.11.7
    • 0.11.8
    • 0.11.9
    • 0.12
    • 0.12.1
    • 0.12.2
    • 0.13
    • 0.14
    • 0.14.1
    • 0.15.0
    • 0.15.1
    • 0.15.2
    • 0.15.3
    • 0.15.4
    • 0.15.5
    • 0.15.6
    • 0.16.0
    • 0.16.1
    • 0.2
    • 0.3
    • 0.3.1
    • 0.4
    • 0.4.1
    • 0.5
    • 0.5.1
    • 0.6
    • 0.6.1
    • 0.6.2
    • 0.7
    • 0.7.1
    • 0.7.2
    • 0.8
    • 0.8.1
    • 0.8.2
    • 0.8.3
    • 0.9
    • 0.9.1
    • 0.9.2
    • 0.9.3
    • 0.9.4
    • 0.9.5
    • 0.9.6
    • 1.0.0
    • 1.0.0rc1
    • 1.0.1
    • 2.0.0
    • 2.0.0rc1
    • 2.0.0rc2
    • 2.0.0rc3
    • 2.0.0rc4
    • 2.0.0rc5
    • 2.0.1
    • 2.0.2
    • 2.0.3
    • 2.1.0
    • 2.1.1
    • 2.1.2
    • 2.2.0
    • 2.2.0a1
    • 2.2.1
    • 2.2.2
    • 2.2.3
    • 2.3.0
    • 2.3.1
    • 2.3.2
    • 2.3.3
    • 2.3.4
    • 2.3.5
    • 2.3.6
    • 2.3.7
    • 2.3.8
    • 3.0.0
    • 3.0.1
    • 3.0.2
    • 3.0.3
    • 3.0.4
    • 3.0.5
    • 3.0.6
    • 3.1.0
    • 3.1.1
    • 3.1.2
    • 3.1.3
    • 3.1.4
    • 3.1.5
    • 3.1.6
    • 3.1.7
    • 3.1.8
    Affected ranges
    • ECOSYSTEM: < 3.1.9

    Update to 3.1.9

  • python-werkzeug Ubuntu:Pro:16.04:LTS

    Versions
    • 0.10.4+dfsg1-1ubuntu1
    • 0.10.4+dfsg1-1ubuntu1.1
    • 0.10.4+dfsg1-1ubuntu1.2
    • 0.10.4+dfsg1-1ubuntu1.2+esm1
    • 0.10.4+dfsg1-1ubuntu1.2+esm2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-werkzeug Ubuntu:Pro:18.04:LTS

    Versions
    • 0.12.2+dfsg1-2
    • 0.13+dfsg1-1
    • 0.14.1+dfsg1-1
    • 0.14.1+dfsg1-1ubuntu0.1
    • 0.14.1+dfsg1-1ubuntu0.2
    • 0.14.1+dfsg1-1ubuntu0.2+esm1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-werkzeug Ubuntu:20.04:LTS

    Versions
    • 0.14.1+dfsg1-4
    • 0.15.6+dfsg1-1
    • 0.16.0+dfsg1-1
    • 0.16.1+dfsg1-1ubuntu1
    • 0.16.1+dfsg1-2
    • 0.16.1+dfsg1-2ubuntu0.1
    • 0.16.1+dfsg1-2ubuntu0.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-werkzeug Ubuntu:22.04:LTS

    Versions
    • 1.0.1+dfsg1-2
    • 2.0.2+dfsg1-1
    • 2.0.2+dfsg1-1ubuntu0.22.04.1
    • 2.0.2+dfsg1-1ubuntu0.22.04.2
    • 2.0.2+dfsg1-1ubuntu0.22.04.3
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-werkzeug Ubuntu:24.04:LTS

    Versions
    • 2.2.2-3
    • 3.0.1-1
    • 3.0.1-2
    • 3.0.1-3
    • 3.0.1-3ubuntu0.1
    • 3.0.1-3ubuntu0.2
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-werkzeug Ubuntu:26.10

    Versions
    • 3.1.5-1
    • 3.1.8-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

  • python-werkzeug Ubuntu:26.04:LTS

    Versions
    • 3.1.3-2
    • 3.1.4-1
    • 3.1.5-1
    Affected ranges
    • ECOSYSTEM: (−∞, +∞)

    No fix published

Original sources

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