CVE-2026-21860

MEDIUM

Werkzeug < 3.1.5 - Path Traversal via Windows Device Name Bypass

Title source: llm
STIX 2.1

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.

References (2)

Core 2

Scores

CVSS v3 5.3
EPSS 0.0042
EPSS Percentile 33.8%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact partial

Details

CWE
CWE-67
Status published
Products (2)
palletsprojects/werkzeug < 3.1.5
pypi/Werkzeug 0 - 3.1.5PyPI
Published Jan 08, 2026
Tracked Since Feb 18, 2026