CVE-2025-21334Known exploitation

SYSTEM privilege escalation via VSP use-after-free

Published Jan 14, 2025 · Updated Jun 9, 2026

Use-after-free in Microsoft Windows Hyper-V NT Kernel Integration VSP allows local users to gain SYSTEM privileges. The VSP dereferences a kernel object after its lifetime ends, allowing reused memory to redirect privileged execution. Existing low-privilege code execution on an affected Windows host is required; successful exploitation yields full local control.

CVSS severity7.8
High
EPSS probability1.56%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Use-after-free in Microsoft Windows Hyper-V NT Kernel Integration VSP allows local users to gain SYSTEM privileges. The VSP dereferences a kernel object after its lifetime ends, allowing reused memory to redirect privileged execution. Existing low-privilege code execution on an affected Windows host is required; successful exploitation yields full local control.

The record

CVE
CVE-2025-21334
Published
Jan 14, 2025
Updated
Jun 9, 2026
Vendor
Microsoft
Product
Windows Server 2025 (Server Core installation)
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 9, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=10.0.26100.0 <10.0.26100.2894

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Microsoft · Windows Server 2025 (Server Core installation)version=10.0.26100.0 <10.0.26100.2894
Microsoft · Windows 11, version 24H2version=10.0.26100.0 <10.0.26100.2894
Microsoft · Windows 10 Version 21H2version=10.0.19044.0 <10.0.19044.5371
Microsoft · Windows Server 2022, 23H2 Edition (Server Core installation)version=10.0.25398.0 <10.0.25398.1369
Microsoft · Windows 11 Version 22H3version=10.0.22631.0 <10.0.22631.4751
Microsoft · Windows 10 Version 22H2version=10.0.19045.0 <10.0.19045.5371
Microsoft · Windows 11 Version 23H2version=10.0.22631.0 <10.0.22631.4751
Microsoft · Windows 11, version 22H2version=10.0.22621.0 <10.0.22621.4751
Microsoft · Windows Server 2025version=10.0.26100.0 <10.0.26100.2894

Published CVSS scores

7.8MicrosoftCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo