CVE-2026-50399 Windows Kernel Elevation of Privilege Vulnerability
An out-of-bounds read in the Windows Kernel allows a 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-2026-50399?
CVE-2026-50399 is a high-severity memory corruption vulnerability in Microsoft Windows 10 21h2, published on 14 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Out-of-bounds read in Windows Kernel allows an authorized attacker to elevate privileges locally.
Weakness: CWE-125
Which versions are affected by CVE-2026-50399?
It affects 7 products.
Products include Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1, Microsoft Windows Server 2022 and 1 more.
How do I fix CVE-2026-50399?
No fix has been published for CVE-2026-50399 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-50399 being exploited?
There is no known exploitation of CVE-2026-50399 in the wild and no public exploit code.
Other vulnerabilities in Microsoft Windows 10 21h2
- CVE-2025-21333 Microsoft Windows Hyper-V NT Kernel Integration VSP Heap-based Buffer Overflow
- CVE-2025-21334 Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free
- CVE-2025-21335 Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free
- CVE-2026-42904 Windows TCP/IP Elevation of Privilege Vulnerability
- CVE-2026-105733 Windows Hyper-V Remote Code Execution Vulnerability
Sources
Also known as GHSA-2h9c-p959-263w.