CVE-2026-20863: Win32k Elevation of Privilege Vulnerability

Overview

Severity

High (CVSS 7)

CVSS Vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Category

Elevation of Privilege

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2026-Jan

Released

2026-01-13

EPSS Score

0.03% (percentile: 9.2%)

Description

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

FAQ

According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability? Successful exploitation of this vulnerability requires an attacker to win a race condition. What privileges could be gained by an attacker who successfully exploited this vulnerability? An attacker who successfully exploited this vulnerability could gain SYSTEM privileges.

Affected Products (11)

Windows

• Windows Server 2022
• Windows Server 2022 (Server Core installation)
• Windows Server 2025 (Server Core installation)
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 23H2 for ARM64-based Systems
• Windows 11 Version 23H2 for x64-based Systems
• Windows Server 2022, 23H2 Edition (Server Core installation)
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows Server 2025

Security Updates (5)

• 5073457
• 5073379
• 5074109
• 5073455
• 5073450

Acknowledgments

<a href="https://infosec.exchange/@ynwarcs">goodbyeselene</a>

Revision History

• 2026-01-13: Information published.