CVE-2026-20876

Windows Virtualization-Based Security (VBS) Enclave Elevation of Privilege Vulnerability

CVE-2026-20876 is fixed in 9 products on 1 platform, first by KB5073455, released January 13, 2026. It is not reported as exploited. Patch Radar priority: Urgent.

Urgent

CVSS

6.7

Critical

Exploitation

None reported

Exploitation Less Likely

CISA KEV

Not listed

Not in the Known Exploited Vulnerabilities catalog

EPSS

0.0051

43rd percentile

<p>Heap-based buffer overflow in Windows Virtualization-Based Security (VBS) Enclave allows an authorized attacker to elevate privileges locally.</p>

Where it's fixed

Product	Fixed in	Fix	Released
Microsoft
Windows 11 Version 23H2 for ARM64-based Systems	22631.6491	KB5073455	Jan 13, 2026
Windows 11 Version 23H2 for x64-based Systems	22631.6491	KB5073455	Jan 13, 2026
Windows 11 Version 24H2 for ARM64-based Systems		KB5074109	Jan 13, 2026
Windows 11 Version 24H2 for x64-based Systems		KB5074109	Jan 13, 2026
Windows 11 Version 25H2 for ARM64-based Systems		KB5074109	Jan 13, 2026
Windows 11 Version 25H2 for x64-based Systems		KB5074109	Jan 13, 2026
Windows Server 2022, 23H2 Edition (Server Core installation)	25398.2092	KB5073450	Jan 13, 2026
Windows Server 2025	26100.32230	KB5073379	Jan 13, 2026
Windows Server 2025 (Server Core installation)	26100.32230	KB5073379	Jan 13, 2026

Details

Published
January 13, 2026
Weakness
Heap-based Buffer Overflow
Vendor advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-20876

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