Improper Handling of Windows Device Names Affecting py3-werkzeug package, versions <3.1.5-r0


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.48% (39th percentile)

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  • Snyk IDSNYK-ALPINE324-PY3WERKZEUG-17297972
  • published11 Jun 2026
  • disclosed8 Jan 2026

Introduced: 8 Jan 2026

CVE-2026-21860  (opens in a new tab)
CWE-67  (opens in a new tab)

How to fix?

Upgrade Alpine:3.24 py3-werkzeug to version 3.1.5-r0 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream py3-werkzeug package and not the py3-werkzeug package as distributed by Alpine. See How to fix? for Alpine:3.24 relevant fixed versions and status.

Werkzeug is a comprehensive WSGI web application library. Prior to version 3.1.5, Werkzeug's safe_join function allows path segments with Windows device names that have file extensions or trailing spaces. On Windows, there are special device names such as CON, AUX, etc that are implicitly present and readable in every directory. Windows still accepts them with any file extension, such as CON.txt, or trailing spaces such as CON. This issue has been patched in version 3.1.5.

CVSS Base Scores

version 3.1