Medium · 6.5 CVE-2025-53809 EUVD-2025-27321GHSA-45gp-pfc8-39m2

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

Published Sep 9, 2025 · Updated Feb 20, 2026 · Assigned by microsoft

Vendor: Microsoft Product: Windows 11 Version 24H2 Product: Windows Server 2025 Product: Windows Server 2025 (Server Core installation) Platform: Windows

Description

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

Affected products

Vendor	Product	Affected	Fixed
Microsoft	Windows 11 Version 24H2	10.0.26100.0 – < 10.0.26100.6584	10.0.26100.6584
Microsoft	Windows Server 2025	10.0.26100.0 – < 10.0.26100.6584	10.0.26100.6584
Microsoft	Windows Server 2025 (Server Core installation)	10.0.26100.0 – < 10.0.26100.6584	10.0.26100.6584

Advisories 3

WID-SEC-2025-2005 Microsoft Windows und Windows Server: Mehrere Schwachstellen BSI CERT-Bund (WID) · Nov 11, 2025
NCSC-2025-0277 Kwetsbaarheden verholpen in Microsoft Windows NCSC-NL (Netherlands) · Sep 9, 2025
MSRC-CVE-2025-53809 Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability Microsoft Security Response Center · Sep 9, 2025

References

Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability vendor-advisory patch