---
id: "CVE-2025-21335"
kind: "vulnerability"
aliases: ["CVE-2025-21335"]
title: "Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability"
severity: "high"
cvss: 7.8
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Windows", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft windows 10 21h2", "fixed": ["10.0.19044.5371"], "affected": "< 10.0.19044.5371", "ecosystem": "vendor"}, {"name": "microsoft windows 10 22h2", "fixed": ["10.0.19045.5371"], "affected": "< 10.0.19045.5371", "ecosystem": "vendor"}, {"name": "microsoft windows 11 22h2", "fixed": ["10.0.22621.4751"], "affected": "< 10.0.22621.4751", "ecosystem": "vendor"}, {"name": "microsoft windows 11 23h2", "fixed": ["10.0.22631.4751"], "affected": "< 10.0.22631.4751", "ecosystem": "vendor"}, {"name": "microsoft windows 11 24h2", "fixed": ["10.0.26100.2894"], "affected": "< 10.0.26100.2894", "ecosystem": "vendor"}, {"name": "microsoft windows server 2022 23h2", "fixed": ["10.0.25398.1369"], "affected": "< 10.0.25398.1369", "ecosystem": "vendor"}, {"name": "microsoft windows server 2025", "fixed": ["10.0.26100.2894"], "affected": "< 10.0.26100.2894", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "hyper-v", "infrastructure", "multi-user-hosts", "windows", "windows-server"]
not_affected_if: ["fully-patched-systems", "hyper-v-not-enabled"]
published_at: "2025-01-14T00:00:00+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T22:29:05+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2025-21335", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-21335", "first_seen_at": "2026-10-23T22:29:05+00:00"}]
---

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

A use-after-free bug in the Windows Hyper-V NT Kernel Integration VSP lets a local user corrupt kernel memory. An attacker who already has a local account can gain SYSTEM privileges, and CISA reports it is being exploited in the wild.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Microsoft Windows affected ? fixed ?
- vendor:microsoft windows 10 21h2 affected < 10.0.19044.5371 fixed 10.0.19044.5371
- vendor:microsoft windows 10 22h2 affected < 10.0.19045.5371 fixed 10.0.19045.5371
- vendor:microsoft windows 11 22h2 affected < 10.0.22621.4751 fixed 10.0.22621.4751
- vendor:microsoft windows 11 23h2 affected < 10.0.22631.4751 fixed 10.0.22631.4751
- vendor:microsoft windows 11 24h2 affected < 10.0.26100.2894 fixed 10.0.26100.2894
- vendor:microsoft windows server 2022 23h2 affected < 10.0.25398.1369 fixed 10.0.25398.1369
- vendor:microsoft windows server 2025 affected < 10.0.26100.2894 fixed 10.0.26100.2894

## How to check

Check the installed Windows build against Microsoft's January 2025 security update for CVE-2025-21335 (unknown exact build numbers in sources)
Run Get-WindowsFeature or check Hyper-V role presence on hosts (unknown exact command in sources)

## Fix

Install the Microsoft January 2025 Windows security update for CVE-2025-21335
If patching is not possible, follow Microsoft's mitigation guidance (unknown in sources)

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2025-21335
- 2026-10-23T22:29:05+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2025-21335

## From the sources

Microsoft Windows Hyper-V NT Kernel Integration VSP contains a use-after-free vulnerability that allows a local attacker to gain SYSTEM privileges.

CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_