#VU121248 Heap-based buffer overflow in Windows Server and Windows - CVE-2026-20876
Published: January 13, 2026
Vulnerability identifier: #VU121248
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-20876
CWE-ID: CWE-122
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerable software:
Windows Server
Windows
Windows Server
Windows
Software vendor:
Microsoft
Microsoft
Description
The vulnerability allows a local user to escalate privileges on the target system.
The vulnerability exists due to a boundary error in Windows Virtualization-Based Security (VBS) Enclave. A local administrator can pass specially crafted data to the application, trigger a heap-based buffer overflow and gain elevated privileges on the target system.
Remediation
Install updates from vendor's website.