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MSRC compact vulnerability detail

CVE-2026-21242 · Windows Subsystem for Linux Elevation of Privilege Vulnerability

Use after free in Windows Subsystem for Linux allows an authorized attacker to elevate privileges locally.

Severity
Important
Impact
Elevation of Privilege
CVSS
7.0 base · 6.1 temporal
Release
2026-02-10
Signals
Windows Subsystem for Linux Elevation of Privilege Exploited: No Publicly disclosed: No Exploitability: Exploitation Less Likely
CWE
CWE-416: Use After Free
Patch Diff
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Resolved binary override
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Description
Use after free in Windows Subsystem for Linux allows an authorized attacker to elevate privileges locally.
FAQ / Articles
Windows Subsystem for Linux Elevation of Privilege Vulnerability
Use after free in Windows Subsystem for Linux allows an authorized attacker to elevate privileges locally.
FAQ
What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.
FAQ
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? For an attacker to exploit this vulnerability, they would need to have knowledge of a specific operation that triggers a memory allocation failure, specifically a use after free.