CVE-2025-53809: Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability

Overview

Severity

Medium (CVSS 6.5)

CVSS Vector

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

Category

Denial of Service

Exploit Status

Not Exploited

Exploitation Likelihood

Less Likely

Patch Tuesday

2025-Sep

Released

2025-09-09

EPSS Score

0.32% (percentile: 54.7%)

Description

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

Affected Products (4)

Windows

• Windows Server 2025 (Server Core installation)
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows Server 2025

Security Updates (2)

• 5065426
• 5065474

Acknowledgments

<a href="https://x.com/skelsec">Tamas Jos (@skelsec)</a>

Revision History

• 2025-09-09: Information published.