Feb 2026: Windows Subsystem for Linux Elevation of Privilege Vulnerability
CVE-2026-21237 Published on February 10, 2026

Windows Subsystem for Linux Elevation of Privilege Vulnerability
Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Subsystem for Linux allows an authorized attacker to elevate privileges locally.

Vendor Advisory NVD

Weakness Types

What is a Race Condition Vulnerability?

The program contains a code sequence that can run concurrently with other code, and the code sequence requires temporary, exclusive access to a shared resource, but a timing window exists in which the shared resource can be modified by another code sequence that is operating concurrently.

CVE-2026-21237 has been classified to as a Race Condition vulnerability or weakness.

What is a Dangling pointer Vulnerability?

Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code.

CVE-2026-21237 has been classified to as a Dangling pointer vulnerability or weakness.

Products Associated with CVE-2026-21237

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Microsoft Windows Server 2022

Microsoft Windows 10

Microsoft Windows Server 2025

Microsoft Windows 11 25h2

Microsoft Windows 11 23h2

Microsoft Windows Server 23h2

Microsoft Windows 11 24h2

Microsoft Windows 11 26h1

Affected Versions

Microsoft Windows 10 Version 21H2:

Version 10.0.19044.0 and below 10.0.19044.6937 is affected.

Microsoft Windows 10 Version 22H2:

Version 10.0.19045.0 and below 10.0.19045.6937 is affected.

Microsoft Windows 11 version 22H3:

Version 10.0.22631.0 and below 10.0.22631.6649 is affected.

Microsoft Windows 11 Version 23H2:

Version 10.0.22631.0 and below 10.0.22631.6649 is affected.

Microsoft Windows 11 Version 24H2:

Version 10.0.26100.0 and below 10.0.26100.7840 is affected.

Microsoft Windows 11 Version 25H2:

Version 10.0.26200.0 and below 10.0.26200.7840 is affected.

Microsoft Windows 11 version 26H1:

Version 10.0.28000.0 and below 10.0.28000.1575 is affected.

Microsoft Windows 11 Version 26H1:

Version 10.0.28000.0 and below 10.0.28000.1575 is affected.

Microsoft Windows Server 2022:

Version 10.0.20348.0 and below 10.0.20348.4773 is affected.

Microsoft Windows Server 2022, 23H2 Edition (Server Core installation):

Version 10.0.25398.0 and below 10.0.25398.2149 is affected.

Microsoft Windows Server 2025:

Version 10.0.26100.0 and below 10.0.26100.32370 is affected.

Microsoft Windows Server 2025 (Server Core installation):

Version 10.0.26100.0 and below 10.0.26100.32370 is affected.

Exploit Probability

EPSS

0.02%

Percentile

4.55%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.