What is the CVSS score of CVE-2025-53809?

CVE-2025-53809 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H. EPSS exploitation probability: 0.3%.

Which versions of Windows 11 24h2 are affected by CVE-2025-53809?

CVE-2025-53809 presents notable security risk, a input validation vulnerability rated CVSS 6.5. Exploitation could compromise the security of affected deployments.

How to fix or mitigate CVE-2025-53809?

Within 30 days: Identify affected systems and apply vendor patches as part of regular patch cycle. Monitor vendor channels for patch availability.

Windows 11 24h2 CVE-2025-53809

MEDIUM

Improper Input Validation (CWE-20)

2025-09-09 secure@microsoft.com

Microsoft Information Disclosure Windows 11 24h2 Windows Server 2025 Windows

6.5

CVSS 3.1 · NVD

Severity by source

NVD PRIMARY

6.5 MEDIUM

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

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

Attack Vector

Network

Attack Complexity

Low

Privileges Required

Low

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Lifecycle Timeline

Analysis Generated

Mar 28, 2026 - 19:11 vuln.today

CVE Published

Sep 09, 2025 - 17:15 nvd

MEDIUM 6.5

DescriptionCVE.org

Improper input validation in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network.

AnalysisAI

Improper input validation in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, low attack complexity. No vendor patch available.

Technical ContextAI

This vulnerability is classified under CWE-20. Improper input validation in Windows Local Security Authority Subsystem Service (LSASS) allows an authorized attacker to deny service over a network. Affected products include: Microsoft Windows 11 24H2, Microsoft Windows Server 2025.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

CVE-2025-53809 vulnerability details – vuln.today

Back

Windows 11 24h2 CVE-2025-53809

Severity by source

CVSS VectorNVD

Lifecycle Timeline

DescriptionCVE.org

AnalysisAI

Technical ContextAI

RemediationAI

Share

External POC / Exploit Code