# CVE-2025-21333: Microsoft Windows Hyper-V NT Kernel Integration VSP Heap-based Buffer Overflow

> An attacker can exploit a memory corruption flaw in Windows Hyper-V to gain elevated privileges on the host system.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C`)
- **Exploited in the wild:** Yes, since 14 Jan 2025 (CISA KEV)
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 14 Jan 2025
- **Updated:** 9 Jun 2026
- **Also known as:** GHSA-gjv6-pfh4-3rff

## What is CVE-2025-21333?

CVE-2025-21333 is a high-severity memory corruption vulnerability in Microsoft Windows 10 21h2, published on 14 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

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

Weakness: CWE-122 (Heap-based Buffer Overflow)

## Which versions are affected by CVE-2025-21333?

It affects 7 products.


Products: 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.

## How do I fix CVE-2025-21333?

No fix has been published for CVE-2025-21333 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 4 Feb 2025.

## Is CVE-2025-21333 being exploited?

Yes. Attackers have exploited CVE-2025-21333 in the wild since at least 14 Jan 2025.

Public exploit code:

- POC exploit for CVE-2025-21333 heap-based buffer overflow. It leverages WNF state data and I/O ring IOP_MC_BUFFER_ENTRY (github_poc): https://github.com/MrAle98/CVE-2025-21333-POC
- LPE due to integer truncation in vskrnlintvsp.sys (github_poc): https://github.com/nu1lptr0/CVE-2025-21333
- KQL para deteccion de CVE-2025-21333 en Sentinel (github_poc): https://github.com/aleongx/KQL_sentinel_CVE-2025-21333
- Microsoft Windows Server 2025 Hyper-V NT Kernel Integration VSP - Elevation of Privilege (exploitdb)
- https://github.com/uname1able/CVE-2025-21333 (github_poc): https://github.com/uname1able/CVE-2025-21333

## Other vulnerabilities in Microsoft Windows 10 21h2

- [CVE-2025-21334](https://insights.sbomify.com/CVE-2025-21334/): Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free (high 7.8, exploited in the wild)
- [CVE-2025-21335](https://insights.sbomify.com/CVE-2025-21335/): Microsoft Windows Hyper-V NT Kernel Integration VSP Use-After-Free (high 7.8, exploited in the wild)
- [CVE-2026-42904](https://insights.sbomify.com/CVE-2026-42904/): Windows TCP/IP Elevation of Privilege Vulnerability (critical 9.6)
- [CVE-2026-105733](https://insights.sbomify.com/CVE-2026-105733/): Windows Hyper-V Remote Code Execution Vulnerability (high 8.8)
- [CVE-2026-69945](https://insights.sbomify.com/CVE-2026-69945/): Windows AppX Deployment Extensions Elevation of Privilege Vulnerability (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-21333 and fix it if it is affected.

What it is: CVE-2025-21333 is a high-severity memory corruption vulnerability in Microsoft Windows 10 21h2, published on 14 Jan 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2025-21333 in the wild since at least 14 Jan 2025.

Affected product: Microsoft Windows 10 21h2. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-21333/ (Markdown: https://insights.sbomify.com/CVE-2025-21333/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-21333
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-21333
- OSV: https://osv.dev/vulnerability/CVE-2025-21333

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-21333/
Summaries are generated and may contain mistakes; the official description above is the record.