CVE-2026-42915 Microsoft Windows VMSwitch Denial of Service Vulnerability
An authorized local attacker can cause a denial of service in Windows VMSwitch due to incorrect buffer size calculation.
- 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-2026-42915?
CVE-2026-42915 is a medium-severity denial of service vulnerability in Microsoft Windows 10 21h2, published on 9 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Incorrect calculation of buffer size in Windows VMSwitch allows an authorized attacker to deny service locally.
Weakness: CWE-131
Which versions are affected by CVE-2026-42915?
It affects 8 products.
Products include Microsoft Windows 10 21h2, Microsoft Windows 10 22h2, Microsoft Windows 11 23h2, Microsoft Windows 11 24h2, Microsoft Windows 11 25h2, Microsoft Windows 11 26h1 and 2 more.
How do I fix CVE-2026-42915?
No fix has been published for CVE-2026-42915 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-42915 being exploited?
There is no known exploitation of CVE-2026-42915 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-3pg4-4j29-q4rr.