Cyber Posture

CVE-2025-21333

HighCISA KEVActive ExploitationPublic PoC

Published: 14 January 2025

Published
14 January 2025
Modified
03 November 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 0.8228 99.2th percentile
Risk Priority 85 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-21333 is a high-severity Heap-based Buffer Overflow (CWE-122) vulnerability in Microsoft Windows 10 21H2. 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 0.8% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified are NIST 800-53 SI-2 (Flaw Remediation) and AC-6 (Least Privilege).

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 mitigates CVE-2025-21333 by requiring timely patching of the Hyper-V NT Kernel Integration VSP elevation of privilege vulnerability.

prevent

Provides memory protections that mitigate heap-based buffer overflow exploits (CWE-122) underlying the privilege escalation in Hyper-V.

prevent

Enforces least privilege to restrict low-privileged local attackers from accessing or exploiting the Hyper-V VSP component.

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 in the Windows Hyper-V NT Kernel Integration VSP component, directly matching T1068 as an exploit that allows a low-privileged attacker to gain high-impact elevated privileges.

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

NVD Description

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

Deeper analysisAI

CVE-2025-21333 is an elevation of privilege vulnerability in the Windows Hyper-V NT Kernel Integration VSP component. It affects Windows Hyper-V, with 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), classified under CWE-122 and NVD-CWE-noinfo. The issue was published on January 14, 2025.

A local attacker with low privileges can exploit this vulnerability with low complexity and no user interaction required. Successful exploitation allows the attacker to gain high-impact confidentiality, integrity, and availability, potentially elevating privileges within the Hyper-V environment.

Microsoft's MSRC advisory provides an update guide for patching, while Vicarius shares Microsoft-provided detection and mitigation scripts. The vulnerability is listed in CISA's Known Exploited Vulnerabilities catalog.

A public exploit is available on Exploit-DB (ID 52436), indicating active real-world exploitation potential.

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
microsoft
windows 11 23h2
≤ 10.0.22631.4751
microsoft
windows 11 24h2
≤ 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

CVE-2025-21418Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-21335Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-21334Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-24066Same product: Microsoft Windows 10 21H2
CVE-2025-26634Same product: Microsoft Windows 10 21H2
CVE-2026-20864Same product: Microsoft Windows 10 21H2
CVE-2025-62215Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-62221Same product: Microsoft Windows 10 21H2both on KEV
CVE-2025-24995Same product: Microsoft Windows 10 21H2
CVE-2025-24067Same product: Microsoft Windows 10 21H2

References