CVE-2026-21860
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.
Scoring
- Severity
- MEDIUM
- CVSS base score
- 6.3
- CVSS vector
- 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
- EPSS probability
- 0.48%
- CWE
- CWE-67
- Published
- 2026-01-08
- Last modified
- 2026-03-12
Affected products
- pallets werkzeug
Weakness type
Related vulnerabilities
- CVE-2026-27199 — Werkzeug safe_join() allows Windows special device names
- CVE-2025-66221 — Werkzeug safe_join() allows Windows special device names
- CVE-2024-51745 — Wasmtime doesn't fully sandbox all the Windows device filenames
- CVE-2024-35197 — gix refs and paths with reserved Windows device names access the devices