What is the CVSS score of CVE-2025-21334?

CVE-2025-21334 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 6.6%.

Which versions of Windows 10 21h2 are affected by CVE-2025-21334?

CVE-2025-21334 presents notable security risk, a use-after-free vulnerability rated CVSS 7.8. Exploitation could compromise the security of affected deployments.. A patch is available.

Is CVE-2025-21334 being actively exploited?

Yes, CVE-2025-21334 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, confirming active in-the-wild exploitation. Immediate patching is required.

How to fix or mitigate CVE-2025-21334?

Within 24 hours: Identify all affected systems and apply vendor patches immediately. If patching is delayed, consider network segmentation to limit exposure.

Windows 10 21h2 CVE-2025-21334

HIGH

Use After Free (CWE-416)

2025-01-14 secure@microsoft.com

Microsoft Memory Corruption Use After Free Information Disclosure Windows 10 21h2 Windows 10 22h2 Windows 11 22h2 Windows 11 23h2 Windows 11 24h2 Windows Server 2022 23h2 Windows Server 2025 Windows

7.8

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

7.8 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Local

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 18:03 vuln.today

Patch released

Mar 28, 2026 - 18:03 nvd

Patch available

Added to CISA KEV

Oct 27, 2025 - 17:13 cisa

CISA KEV

CVE Published

Jan 14, 2025 - 18:15 nvd

HIGH 7.8

DescriptionCVE.org

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

AnalysisAI

Windows Hyper-V NT Kernel Integration VSP contains a use-after-free vulnerability allowing local privilege escalation, the second of three Hyper-V zero-days in January 2025.

Technical ContextAI

The CWE-416 use-after-free in the VSP component allows accessing freed memory during Hyper-V service operations, enabling privilege escalation.

RemediationAI

Apply January 2025 security updates. All three Hyper-V CVEs must be patched simultaneously.

CVE-2025-21334 vulnerability details – vuln.today

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Windows 10 21h2 CVE-2025-21334

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

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External POC / Exploit Code