Cyber Posture

CVE-2025-21335

HighCISA KEVActive Exploitation

Published: 14 January 2025

Published
14 January 2025
Modified
27 October 2025
KEV Added
14 January 2025
Patch
CVSS Score 7.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.0765 91.9th percentile
Risk Priority 40 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21335 is a high-severity Use After Free (CWE-416) vulnerability in Microsoft Windows 11 22H2. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 8.1% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.

The strongest mitigations our analysis identified are NIST 800-53 SI-16 (Memory Protection) and SI-2 (Flaw Remediation).

Threat & Defense at a Glance

What attackers do: exploitation maps to Exploitation for Privilege Escalation (T1068). What defenders deploy: see the NIST 800-53 controls recommended below.
Threat & Defense Details

Mitigating Controls (NIST 800-53 r5)AI

prevent

Directly remediates the Use After Free flaw in Windows Hyper-V VSP by requiring timely application of Microsoft patches as referenced in MSRC and CISA KEV.

prevent

Implements memory safeguards such as ASLR and DEP to protect against unauthorized code execution from Use After Free vulnerabilities in Hyper-V kernel components.

prevent

Enables proactive identification of the Hyper-V VSP vulnerability through regular scanning, facilitating prompt patching to prevent local privilege escalation.

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

The CVE describes a local elevation of privilege vulnerability (use-after-free in Hyper-V kernel component) that directly enables T1068 Exploitation for Privilege Escalation to achieve kernel-level access.

Confidence: HIGH · MITRE ATT&CK Enterprise v18.1

NVD Description

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

Deeper analysisAI

CVE-2025-21335 is an elevation of privilege vulnerability in the Windows Hyper-V NT Kernel Integration VSP component, stemming from a CWE-416 (Use After Free) flaw. Published on January 14, 2025, it carries a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H), indicating high severity with significant impacts on confidentiality, integrity, and availability. The vulnerability affects Windows Hyper-V hosts where the VSP (Virtual Service Provider) integration service mishandles memory, allowing improper object reuse after deallocation.

A local attacker with low privileges on the Hyper-V host can exploit this vulnerability with low complexity and no user interaction required. Successful exploitation enables elevation to higher privilege levels, potentially granting full system control, including kernel-level access, due to the high impact ratings across confidentiality, integrity, and availability.

Microsoft's Security Response Center (MSRC) provides an update guide at https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-21335 detailing patches and remediation steps. The vulnerability is also referenced in the CISA Known Exploited Vulnerabilities catalog at https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-21335, signaling active real-world exploitation and urging federal agencies to apply mitigations promptly.

Details

CWE(s)
KEV Date Added
14 January 2025

Affected Products

microsoft
windows 10 21h2
≤ 10.0.19044.5371
microsoft
windows 10 22h2
≤ 10.0.19045.5371
microsoft
windows 11 22h2
≤ 10.0.22621.4751 · ≤ 10.0.22621.4751
microsoft
windows 11 23h2
≤ 10.0.22631.4751 · ≤ 10.0.22631.4751
microsoft
windows 11 24h2
≤ 10.0.26100.2894 · ≤ 10.0.26100.2894
microsoft
windows server 2022 23h2
≤ 10.0.25398.1369
microsoft
windows server 2025
≤ 10.0.26100.2894

CVEs Like This One

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CVE-2026-26132Same product: Microsoft Windows 10 21H2
CVE-2026-20923Same product: Microsoft Windows 10 21H2
CVE-2025-62215Same product: Microsoft Windows 10 21H2both on KEV
CVE-2026-20865Same product: Microsoft Windows 10 21H2

References