CVE-2025-53809

Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability

State: Published
Severity: 6.5 Medium
Published: Sep 9, 2025
Updated: Feb 20, 2026
Reserved: Jul 9, 2025

Description

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

Scores

CVSS	Score	Vector	Source
3.1	6.5 Medium	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C	microsoft

Weaknesses

CWE-20 Improper Input Validation

Affected Products

Product	Versions
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.6584Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.6584Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.6584Affected

References

Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerabilityvendor-advisorypatch

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