Skip to main content

Windows CVE-2026-21860

MEDIUM
Improper Handling of Windows Device Names (CWE-67)
2026-01-08 security-advisories@github.com GHSA-87hc-h4r5-73f7
5.3
CVSS 3.1 · GitHub Advisory
Share

Severity by source

GitHub Advisory PRIMARY
5.3 MEDIUM
AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
SUSE
MEDIUM
qualitative

Primary rating from GitHub Advisory.

CVSS VectorGitHub Advisory

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
Low

Lifecycle Timeline

3
Analysis Generated
Mar 12, 2026 - 21:54 vuln.today
Patch released
Feb 02, 2026 - 17:15 nvd
Patch available
CVE Published
Jan 08, 2026 - 19:15 nvd
MEDIUM 5.3

Blast Radius

ecosystem impact
† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth
  • 33 pypi packages depend on werkzeug (28 direct, 5 indirect)

Ecosystem-wide dependent count for version 3.1.5.

DescriptionGitHub Advisory

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.

AnalysisAI

Werkzeug versions prior to 3.1.5 fail to properly validate Windows reserved device names in the safe_join function, allowing attackers to bypass path restrictions by using device names with file extensions or trailing spaces (e.g., CON.txt, AUX ). This denial of service vulnerability affects Windows systems running vulnerable Werkzeug versions and could allow an unauthenticated remote attacker to access restricted files or cause application crashes. A patch is available in version 3.1.5 and later.

Technical ContextAI

Affects Werkzeug. 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.

RemediationAI

A vendor patch is available — apply it immediately. Fixed in version 3.1.5.. Restrict network access to the affected service where possible.

CVE-2021-40444 HIGH POC
8.8 Sep 15

Windows MSHTML component contains a remote code execution vulnerability that allows attackers to craft malicious ActiveX

CVE-2021-1732 HIGH POC
7.8 Feb 25

Windows Win32k contains an out-of-bounds write vulnerability enabling local privilege escalation to SYSTEM, exploited by

CVE-2018-8174 HIGH POC
7.5 May 09

The Windows VBScript engine contains a remote code execution vulnerability in object handling that allows full system co

CVE-2019-0803 HIGH POC
7.8 Apr 09

Windows Win32k fails to properly handle objects in memory, allowing local privilege escalation exploited in the wild in

CVE-2020-1472 MEDIUM POC
5.5 Aug 17

A privilege escalation vulnerability (CVSS 5.5). Risk factors: actively exploited (KEV-listed), EPSS 94% exploitation pr

CVE-2024-30088 HIGH POC
7.0 Jun 11

Windows Kernel contains a TOCTOU race condition vulnerability allowing local privilege escalation, exploited by the OilR

CVE-2025-33053 HIGH POC
8.8 Jun 10

Windows Internet Shortcut Files (.url) contain an external control vulnerability (CVE-2025-33053, CVSS 8.8) that enables

CVE-2025-33073 HIGH POC
8.8 Jun 10

Windows SMB contains an improper access control vulnerability (CVE-2025-33073, CVSS 8.8) enabling authenticated attacker

CVE-2025-13315 CRITICAL POC
9.3 Nov 19

Twonky Server 8.5.2 on Linux and Windows allows unauthenticated access to the admin log file through a web service API b

CVE-2013-10047 CRITICAL POC
9.3 Aug 01

An unrestricted file upload vulnerability exists in MiniWeb HTTP Server <= Build 300 that allows unauthenticated remote

CVE-2012-10030 CRITICAL POC
9.3 Aug 05

FreeFloat FTP Server contains multiple critical design flaws that allow unauthenticated remote attackers to upload arbit

CVE-2025-34101 CRITICAL POC
9.3 Jul 10

Serviio Media Server versions 1.4 through 1.8 on Windows contain an unauthenticated command injection in the /rest/actio

Vendor StatusVendor

SUSE

Severity: Medium
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Fixed
SUSE Linux Enterprise High Performance Computing 12 Fixed
SUSE Linux Enterprise High Performance Computing 15 SP7 Fixed
SUSE Linux Enterprise Module for Basesystem 15 SP7 Fixed
SUSE Linux Enterprise Module for Package Hub 15 SP7 Fixed

Share

CVE-2026-21860 vulnerability details – vuln.today

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy