CVE-2025-21333 — Windows Hyper-V NT Kernel Integration VSP Elevation of Privilege Vulnerability

Executive Summary

None

Overview

7.8

CVSS HIGH

Important

MS Severity

Exploited

MS Exploit Status

Exploitation Detected

MS Exploit Likelihood

Category Elevation of Privilege

Weakness CWE-122: Heap-based Buffer Overflow

Released Jan 14 2025

Last Updated Jan 14 2025

Publicly Disclosed No

CISA KEV Listed (added 2025-01-14)

Known Exploits None Known

EPSS Score 0.09988 — 0.9518 percentile

NVD CVSS 7.8 HIGH — matches MSRC

CVSS Vector

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

ATTACK VECTOR

Local

ATTACK COMPLEXITY

Low

PRIVILEGES REQUIRED

Low

USER INTERACTION

None

SCOPE

Unchanged

CONFIDENTIALITY

High

INTEGRITY

High

AVAILABILITY

High

EXPLOIT CODE MATURITY

Unproven

REMEDIATION LEVEL

Official Fix

REPORT CONFIDENCE

Confirmed

Temporal Score: 6.8

EPSS Score

0.09988

probability of exploitation in the next 30 days

0.9518 percentile - updated 2026-08-14

View on FIRST.org

Affected Products

11 affected products

Product	KB Article	Severity	Impact	Restart Required
Windows 10 Version 21H2 for x64-based Systems	`5049981 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 10 Version 22H2 for x64-based Systems	`5049981 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 22H2 for ARM64-based Systems	`5050021 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 22H2 for x64-based Systems	`5050021 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for ARM64-based Systems	`5050021 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 23H2 for x64-based Systems	`5050021 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 24H2 for ARM64-based Systems	`5050009 (Security Update)`	Important	Elevation of Privilege	Yes
Windows 11 Version 24H2 for x64-based Systems	`5050009 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2022, 23H2 Edition (Server Core installation)	`5049984 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2025	`5050009 (Security Update)`	Important	Elevation of Privilege	Yes
Windows Server 2025 (Server Core installation)	`5050009 (Security Update)`	Important	Elevation of Privilege	Yes

Patches

4 patches

Article	Type	Restart
`5049981`	Security Update	Yes
`5050021`	Security Update	Yes
`5050009`	Security Update	Yes
`5049984`	Security Update	Yes

Exploits & PoC

4 public PoCs

Unverified third-party code

Public proof-of-concept repositories aggregated from PoC-in-GitHub. They are not reviewed and may be incomplete, non-functional, or malicious — inspect the code before running anything.

Repository	Stars	Published	Description
MrAle98/CVE-2025-21333-POC	233	2025-02-27	POC exploit for CVE-2025-21333 heap-based buffer overflow. It leverages WNF state data and I/O ring IOP_MC_BUFFER_ENTRY
nu1lptr0/CVE-2025-21333	23	2026-05-05	LPE due to integer truncation in vskrnlintvsp.sys
aleongx/KQL_sentinel_CVE-2025-21333	0	2025-03-11	KQL para deteccion de CVE-2025-21333 en Sentinel
uname1able/CVE-2025-21333	0	2026-07-16

Detection Rules

No public Sigma or Nuclei detection rule has been mapped to this CVE yet. Coverage is concentrated on exploited / high-profile vulnerabilities; check SigmaHQ for updates.

Acknowledgments

Anonymous

References

MSRC Advisory MITRE NVD