CVE-2025-21335
Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free Vulnerability
Does this matter?
Known to be exploited in the wild (CISA KEV, CISA remediation deadline 4 February 2025). Treat as an emergency change: patch or isolate now, then hunt for prior compromise.
Description
Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
- CVSS 3.1
- 7.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 1.40% probability · 72th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Listed 14 January 2025 · due 4 February 2025
- Weakness
- CWE-416
- Affected
- microsoft/windows 10 21h2 · microsoft/windows 10 22h2 · microsoft/windows 11 22h2 · microsoft/windows 11 23h2 · microsoft/windows 11 24h2 · microsoft/windows server 2022 23h2 · microsoft/windows server 2025
- Source
- secure@microsoft.com
EPSS 1.4% since 30 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
CISA notes
Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-21335 ; https://nvd.nist.gov/vuln/detail/CVE-2025-21335
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21335Patch, Vendor Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21335US Government Resource
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.