CVE-2026-21860

MEDIUM EPSS 34.0%
Published Jan 8, 20265mo ago · Modified Jun 17, 20261w ago
6.3 CVSS 4.0
Medium
Find Similar
Published Jan 8, 2026 5mo ago
Last Modified Jun 17, 2026 1w ago

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.

CVSS Details

Base Score
6.3
Exploitability
—
Impact
—
Vector string
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
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope X

Threat Intelligence

EPSS Exploit Probability
34.0% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-67

Affected Products 2

VendorProductVersionRange
palletsprojectswerkzeug* <3.1.5
microsoftwindows*any

References 2

  • github.com https://github.com/pallets/werkzeug/commit/7ae1d254e04a0c33e241ac1cca4783ce6c875ca3
    Patch
  • github.com https://github.com/pallets/werkzeug/security/advisories/GHSA-87hc-h4r5-73f7
    Vendor Advisory

Remediation

  • github.com https://github.com/pallets/werkzeug/commit/7ae1d254e04a0c33e241ac1cca4783ce6c875ca3
    Patch