CVE-2026-20863 Win32k Elevation of Privilege Vulnerability
A double free vulnerability in Windows Win32K allows an authorized local attacker to elevate privileges.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-20863?
CVE-2026-20863 is a high-severity use after free vulnerability in Microsoft Windows 11 23h2, published on 13 Jan 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Double free in Windows Win32K - ICOMP allows an authorized attacker to elevate privileges locally.
Weakness: CWE-415
Which versions are affected by CVE-2026-20863?
It affects 6 products.
Products include Microsoft Windows 11 23h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows Server 2022, Microsoft Windows Server 2022 23h2, Microsoft Windows Server 2025.
How do I fix CVE-2026-20863?
No fix has been published for CVE-2026-20863 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-20863 being exploited?
There is no known exploitation of CVE-2026-20863 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 11 23h2
- CVE-2026-81963 Microsoft Windows Link Following
- CVE-2026-100219 Microsoft QUIC Remote Code Execution Vulnerability
- CVE-2026-96909 Windows BitLocker Remote Code Execution Vulnerability
- CVE-2026-62815 Microsoft QUIC Remote Code Execution Vulnerability
- CVE-2026-45657 Windows Kernel Remote Code Execution Vulnerability
Sources
Also known as GHSA-25wh-jjx3-jq6q.