# CVE-2025-21335: Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability

Source: https://junglewise.ai/threats/cve-2025-21335-microsoft-windows-hyper-v-nt-kernel-integration-vsp-use-after  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-01-14. Updated: 2026-05-09  
License: CC BY 4.0 with a link back

CVE-2025-21335 · Severity: critical · CVSS 7.8 · Exploited in the wild · Published 2025-01-14

A use-after-free vulnerability in the Microsoft Windows Hyper-V NT Kernel Integration VSP allows a local attacker to escalate privileges to SYSTEM level. The vulnerability has been observed being exploited in the wild.

Technologies: [Microsoft Windows](https://junglewise.ai/threats/technologies/windows). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2025-21335 exploited in the wild?** Yes. CVE-2025-21335 is known to be exploited in the wild, first recorded on 14 January 2025. Treat it as urgent.

**How severe is CVE-2025-21335?** Critical severity, with a CVSS score of 7.8, published 14 January 2025.

**Which products and versions are affected?** Microsoft Windows 10 21H2 up to (excluding) 10.0.19044.5371; Microsoft Windows 10 22H2 up to (excluding) 10.0.19045.5371; Microsoft Windows 11 22H2 up to (excluding) 10.0.22621.4751; Microsoft Windows 11 23H2 up to (excluding) 10.0.22631.4751; and 3 more.

**Is there a fix for CVE-2025-21335?** 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-2025-21335 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2025-21335?** 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 21H2 up to (excluding) 10.0.19044.5371
- Microsoft Windows 10 22H2 up to (excluding) 10.0.19045.5371
- Microsoft Windows 11 22H2 up to (excluding) 10.0.22621.4751
- Microsoft Windows 11 23H2 up to (excluding) 10.0.22631.4751
- Microsoft Windows 11 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 Known Exploited Vulnerabilities Catalog
- 2025-01-14: exploited: Reported as exploited in the wild at time of publication.

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