CVE-2026-20920: Win32k Elevation of Privilege Vulnerability

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-01-13 · updated 2026-07-30
Weakness: CWE-416

Description

Use after free in Windows Win32K - ICOMP allows an authorized attacker to elevate privileges locally.

Affected products

Microsoft Windows 11: before 10.0.22631.6491 — fixed in 10.0.22631.6491
Microsoft Windows Server 2022: before 10.0.20348.4648 — fixed in 10.0.20348.4648
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): before 10.0.25398.2092 — fixed in 10.0.25398.2092
Microsoft Windows 11: from 10.0.22631.0 before 10.0.22631.6491 — fixed in 10.0.22631.6491
Microsoft Windows Server 2022: from 10.0.20348.0 before 10.0.20348.4648 — fixed in 10.0.20348.4648
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation): from 10.0.25398.0 before 10.0.25398.2092 — fixed in 10.0.25398.2092

How to fix

Upgrade to a fixed version: Microsoft Windows 11 10.0.22631.6491; Microsoft Windows Server 2022 10.0.20348.4648; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2092; Microsoft Windows 11 10.0.22631.6491; Microsoft Windows Server 2022 10.0.20348.4648; Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.2092. Check the vendor advisory for mitigations.

References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20920

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