MSRC-CVE-2026-20920 — Win32k Elevation of Privilege Vulnerability

Summary

Impact: Elevation of Privilege. Microsoft rating: Important. Not known to be exploited — Exploitation Unlikely. Customer action: Required.

Details

What privileges could be gained by an attacker who successfully exploited this vulnerability?
An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

Security updates
10.0.20348.4648 — https://support.microsoft.com/help/5073457
10.0.22631.6491 — https://support.microsoft.com/help/5073455
10.0.25398.2092 — https://support.microsoft.com/help/5073450

Vulnerabilities 1

High 7.8

CVE-2026-20920

Win32k Elevation of Privilege Vulnerability

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

Microsoft Windows Server 2022 Windows 11 version 23H2 Windows Server 2022, 23H2 Edition (Server Core installation) Windows

Jan 13, 2026

Revision history

2026-01-13 #1
Information published.

References

CVE-2026-20920 Win32k Elevation of Privilege Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20920
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss