CVE-2025-59257

Windows Local Session Manager (LSM) Denial of Service Vulnerability

State: Published
Severity: 6.5 Medium
Published: Oct 14, 2025
Updated: Feb 22, 2026
Reserved: Sep 11, 2025

Description

Improper validation of specified type of input in Windows Local Session Manager (LSM) 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-1287 Improper Validation of Specified Type of Input

Affected Products

Product	Versions
Windows 11 Version 24H2Microsoft	10.0.26100.0 to before 10.0.26100.6899Affected
Windows 11 Version 25H2Microsoft	10.0.26200.0 to before 10.0.26200.6899Affected
Windows Server 2022, 23H2 Edition (Server Core installation)Microsoft	10.0.25398.0 to before 10.0.25398.1913Affected
Windows Server 2025Microsoft	10.0.26100.0 to before 10.0.26100.6899Affected
Windows Server 2025 (Server Core installation)Microsoft	10.0.26100.0 to before 10.0.26100.6899Affected

References

Windows Local Session Manager (LSM) Denial of Service Vulnerabilityvendor-advisorypatch

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