CVEs / CVE-2025-21333
CVE-2025-21333: Microsoft Windows Hyper-V NT Kernel Integration VSP Heap-based Buffer Overflow Vulnerability
- Known exploited in the CISA KEV catalog since 14 Jan 2025
- high 7.8 CVSS 3.1 (from the CNA)
- EPSS 10% chance of exploitation in the next 30 days, higher than 95% of CVEs (30 Oct 2026)
- Last changed at its sources
Are you affected? Check your servers with Stackurity: it lists the software on each server and the vulnerabilities to fix first.
Check your servers with Stackurity Already using Stackurity? Search for CVE-2025-21333
Summary
Microsoft Windows Hyper-V NT Kernel Integration VSP contains a heap-based buffer overflow vulnerability that allows a local attacker to gain SYSTEM privileges.
Description
Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability
Affected and fixed versions
| Product | Affected | Fixed in |
|---|---|---|
| Microsoft Windows 10 Version 21H2 | from 10.0.19044.0, before 10.0.19044.5371 | 10.0.19044.5371 |
| Microsoft Windows 10 Version 22H2 | from 10.0.19045.0, before 10.0.19045.5371 | 10.0.19045.5371 |
| Microsoft Windows 11 version 22H2 | from 10.0.22621.0, before 10.0.22621.4751 | 10.0.22621.4751 |
| Microsoft Windows 11 version 22H3 | from 10.0.22631.0, before 10.0.22631.4751 | 10.0.22631.4751 |
| Microsoft Windows 11 Version 23H2 | from 10.0.22631.0, before 10.0.22631.4751 | 10.0.22631.4751 |
| Microsoft Windows 11 Version 24H2 | from 10.0.26100.0, before 10.0.26100.2894 | 10.0.26100.2894 |
| Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) | from 10.0.25398.0, before 10.0.25398.1369 | 10.0.25398.1369 |
| Microsoft Windows Server 2025 | from 10.0.26100.0, before 10.0.26100.2894 | 10.0.26100.2894 |
| Microsoft Windows Server 2025 (Server Core installation) | from 10.0.26100.0, before 10.0.26100.2894 | 10.0.26100.2894 |
Exploitation
| In CISA KEV since | 14 Jan 2025 |
|---|---|
| Due date for US federal agencies | 4 Feb 2025 |
| Used in ransomware campaigns | Unknown |
| Required action | Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable. |
Severity
| CVSS 3.1 | 7.8 highCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HScored by the CNA ([email protected]) |
|---|---|
| Weakness | CWE-122 |
References
- CVE-2025-21333 on NVD
- CVE-2025-21333 in the CISA KEV catalog
- https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-21333 (cited by CISA)
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21333 Patch, Vendor Advisory
- https://www.exploit-db.com/exploits/52436 Exploit, Third Party Advisory, VDB Entry
- https://www.vicarius.io/vsociety/posts/cve-2025-21333-elevated-privilege-exposure-in-windows-hyper-v-by-microsoft-detection-script Mitigation, Third Party Advisory
- https://www.vicarius.io/vsociety/posts/cve-2025-21333-elevated-privilege-exposure-in-windows-hyper-v-by-microsoft-mitigation-script Mitigation, Third Party Advisory
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21333 US Government Resource
Sources
Exploitation status from the CISA Known Exploited Vulnerabilities catalog. EPSS scores from FIRST. Descriptions, severity and references from the National Vulnerability Database. Open-source package versions from OSV (CC-BY 4.0). Text is shown as each source states it; Stackurity does not edit it. Check the vendor's advisory before acting.
This product uses data from the NVD API but is not endorsed or certified by the NVD.