CVE-2026-20876: Windows Virtualization-Based Security (VBS) Enclave Elevation of Privilege Vulnerability

Overview

Severity

Medium (CVSS 6.7)

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:H/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

0.04% (percentile: 11.6%)

Description

Heap-based buffer overflow in Windows Virtualization-Based Security (VBS) Enclave 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 Virtual Trust Level 2 (VTL2) privileges.

Affected Products (9)

Windows

• 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 (4)

• 5073379
• 5074109
• 5073455
• 5073450

Acknowledgments

Andrey Markovytch and Kas Dekel with Microsoft

Revision History

• 2026-01-13: Information published.