CVE-2026-21860 - Werkzeug Plugin
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.
CVE-2026-21860
MEDIUM
CVSS 6.3
Published 2026-01-08
Updated 2026-02-02
AI Risk Elevated (64/100)
Active Exploit: No strong signal
Published Exploit: Public exploit references found
Priority: P3 Priority
Severity Band
MEDIUM
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Affected Components
1
Reference Links
2
AI Risk Engine
Elevated (64/100)
Exploitability
Medium
Active Exploitation
No strong signal
Published Exploit Status
Public exploit references found
AI Context
Machine-generated threat intelligence
AI
Updated 16 days ago
AI enriched 16 days ago (2026-04-09 08:23 UTC)
Technical 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.
Potential Impact
Severity is MEDIUM (CVSS 6.3). Depending on deployment context, affected components may be exposed to unauthorized actions or data integrity risk.
Exploitability Assessment
Exploitability is assessed as Medium based on published exploit references.
Primary risk drivers: published exploit references
Mitigation Recommendations
Validate affected product versions, prioritize patching, and monitor references for vendor remediation guidance. If immediate patching is not possible, apply compensating controls and limit exposure of vulnerable surfaces.
Detection & Monitoring
Track authentication anomalies, unexpected file writes, and suspicious plugin API activity around affected components.
Business Impact Lens
Prioritize remediation where affected components process customer data, admin sessions, or Internet-exposed workflows.