CVE-2026-83516: Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability

Overview

Severity

High (CVSS 7.5)

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:N/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

Unlikely

Patch Tuesday

2026-Oct

Released

2026-10-13

Description

Out-of-bounds read in Windows Local Security Authority Subsystem Service (LSASS) allows an unauthorized attacker to deny service over a network.

Affected Products (16)

Windows

• Windows 11 Version 26H2 for ARM64-based Systems
• Windows 11 Version 26H2 for x64-based Systems
• Windows 10 Version 1809 for 32-bit Systems
• Windows 10 Version 1809 for x64-based Systems
• Windows Server 2019
• Windows Server 2019 (Server Core installation)
• Windows Server 2022
• Windows Server 2022 (Server Core installation)
• Windows Server 2025 (Server Core installation)
• Windows 11 Version 25H2 for ARM64-based Systems
• Windows 11 Version 25H2 for x64-based Systems
• Windows 11 Version 24H2 for ARM64-based Systems
• Windows 11 Version 24H2 for x64-based Systems
• Windows Server 2025
• Windows 11 version 26H1 for x64-based Systems
• Windows 11 Version 26H1 for ARM64-based Systems

Security Updates (5)

• 5127648
• 5126651
• 5126655
• 5126646
• 5127646

Revision History

• 2026-10-13: Information published.