CVE-2025-21334: Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability

Vulnerability summary

CVE-2025-21334 is a high (CVSS 7.8) Use After Free vulnerability in Microsoft Windows. It is known to be exploited: CISA lists it, first on 14-01-2025. EPSS estimates a 1.57% chance of exploitation in the next 30 days, higher than 75.1% of scored vulnerabilities.

Timeline

1. 14-01-2025
   PublishedVulnerability first disclosed.
2. 14-01-2025
   Added to CISA KEVMicrosoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability
3. 04-02-2025
   CISA remediation dueApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
4. 09-06-2026
   Last modifiedVulnerability information updated.

Description

Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.