#VU121237 Double free in Windows Server and Windows - CVE-2026-20863

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Main Vulnerability Database Vulnerabilities #VU121237

#VU121237 Double free in Windows Server and Windows - CVE-2026-20863

Published: January 13, 2026


Vulnerability identifier: #VU121237
Vulnerability risk: Low
CVSSv4.0: CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-20863
CWE-ID: CWE-415
Exploitation vector: Local access
Exploit availability: No public exploit available
Vulnerable software:
Windows Server
Windows
Software vendor:
Microsoft

Description

The vulnerability allows a local user to escalate privileges on the system.

The vulnerability exists due to a boundary error in Win32k. A local user can pass specially crafted data to the application, trigger double free error and gain elevated privileges on the target system.


Remediation

Install updates from vendor's website.

External links