CVE-2026-21860 (GCVE-0-2026-21860)

Vulnerability from cvelistv5 – Published: 2026-01-08 18:34 – Updated: 2026-01-08 18:50
VLAI
Title
Werkzeug safe_join() allows Windows special device names with compound extensions
Summary
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.
Severity
6.3 (Medium)
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
SSVC
Exploitation: none Automatable: no Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-01-08 18:50 UTC
CWE
  • CWE-67 - Improper Handling of Windows Device Names
Assigner
GitHub_M CNA under the mitre root
CNA scorecard C 72/100 over 7868 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
pallets werkzeug Affected: < 3.1.5
guessed Create a notification for this product.
Show details on NVD website
To clipboard 

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