CVE-2025-21334
Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability
This vulnerability is in the CISA Known Exploited Vulnerabilities catalog: attackers are using it. If you run Windows, fix it now.
CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
US federal civilian agencies must remediate by Feb 4, 2025.
Patch status
Official fix available since
Apply the vendor's update to every affected system. Check the fixed-in versions below where known.
Basis: NVD patch reference
Description
Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
Source: NIST National Vulnerability Database. Official vulnerability data, reproduced as published.
Affected products
| Product | Vendor | Source |
|---|---|---|
| Windows | Microsoft | KEV |
Sources: KEV = CISA Known Exploited Vulnerabilities catalog. Version details have not been published yet.
Intelligence timeline
Developments from the last 30 days, newest first.
- CVSS scoredUpdateKEV
CVE-2025-21334 scored CVSS 7.8: Microsoft Windows, Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability
CISA lists this as exploited in the wild. Unpatched Windows systems are exposed to active attacks now.
Basis: NIST National Vulnerability Database
- Patch releasedUpdateKEV
Patch released for CVE-2025-21334: Microsoft Windows, Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability
An official fix is now available for Microsoft Windows. This vulnerability is being exploited, so apply it promptly.
Basis: NVD patch reference
1 earlier event is available with a subscription. See plans.
Coverage
We have not published a story about this vulnerability yet.