What is the CVSS score of CVE-2025-21335?

CVE-2025-21335 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: 8.7%.

Which versions of Windows are affected by CVE-2025-21335?

CVE-2025-21335 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-2025-21335 being actively exploited?

Yes, CVE-2025-21335 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-2025-21335?

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

Windows CVE-2025-21335

HIGH

Use After Free (CWE-416)

2025-01-14 secure@microsoft.com

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

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

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 for local privilege escalation, the third of three Hyper-V zero-days exploited in January 2025.

Technical ContextAI

The CWE-416 use-after-free provides a third exploitation path through the Hyper-V VSP, reinforcing the systematic nature of the attack against Hyper-V's kernel integration layer.