CVE-2026-21860

MEDIUM

5.3

Description

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.

CVE Details

CVSS v3.1 Score5.3

SeverityMEDIUM

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published1/8/2026

Last Modified2/2/2026

Sourcenvd

Honeypot Sightings0

Affected Products

microsoft:windowspalletsprojects:werkzeug

Weaknesses (CWE)

CWE-67

References

https://github.com/pallets/werkzeug/commit/7ae1d254e04a0c33e241ac1cca4783ce6c875ca3(security-advisories@github.com)

https://github.com/pallets/werkzeug/security/advisories/GHSA-87hc-h4r5-73f7(security-advisories@github.com)

IOC Correlations

No correlations recorded

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