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.
Published:Jan 8, 2026
Last Modified:Apr 18, 2026
EPS:Jan 8, 2026
EPSS Score:0.00022
CVSS Score:5.3
Affected Products
Vendor
Product
Action
Vendor
Microsoft
Product
Windows
Microsoft
Windows
Vendor
Palletsprojects
Product
Werkzeug
Palletsprojects
Werkzeug
Exploits
No exploit reference
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
No CAPEC recorded yet
Related CVEs
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
