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

CVE-2025-21334 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2025-01-14

Microsoft Windows Hyper-V NT Kernel Integration VSP contains a use-after-free vulnerability. A local attacker can exploit this flaw to escalate privileges to SYSTEM level. This vulnerability has been observed being exploited in the wild.

Technologies: Microsoft Windows. Vendors: Microsoft.

Quick answers

Is CVE-2025-21334 exploited in the wild?
Yes. CVE-2025-21334 is known to be exploited in the wild, first recorded on 14 January 2025. Treat it as urgent.
How severe is CVE-2025-21334?
Critical severity, with a CVSS score of 7.8, published 14 January 2025.
Which products and versions are affected?
Microsoft Windows 10 Version 21H2 up to (excluding) 10.0.19044.5371; Microsoft Windows 10 Version 22H2 up to (excluding) 10.0.19045.5371; Microsoft Windows 11 Version 22H2 up to (excluding) 10.0.22621.4751; Microsoft Windows 11 Version 23H2 up to (excluding) 10.0.22631.4751; and 3 more.
Is there a fix for CVE-2025-21334?
A patch was published on 2025-01-14. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2025-21334 attacked?
It is attacked with local access, in an operating system.
Am I affected by CVE-2025-21334?
Check whether you run Microsoft Windows. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Affected products

  • Microsoft Windows 10 Version 21H2 up to (excluding) 10.0.19044.5371
  • Microsoft Windows 10 Version 22H2 up to (excluding) 10.0.19045.5371
  • Microsoft Windows 11 Version 22H2 up to (excluding) 10.0.22621.4751
  • Microsoft Windows 11 Version 23H2 up to (excluding) 10.0.22631.4751
  • Microsoft Windows 11 Version 24H2 up to (excluding) 10.0.26100.2894
  • Microsoft Windows Server 2022 23H2 up to (excluding) 10.0.25398.1369
  • Microsoft Windows Server 2025 up to (excluding) 10.0.26100.2894

Timeline

  • 2025-01-14: disclosed
  • 2025-01-14: patched
  • 2025-01-14: kev added: Added to CISA KEV catalog due to active exploitation.
  • 2025-01-14: exploited

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