High MSRC-CVE-2026-83649 1 CVE

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

Published Oct 13, 2026 · Updated Oct 13, 2026

Vendor: Microsoft

Summary

Impact: Denial of Service. Microsoft rating: Important. Not known to be exploited — Exploitation Unlikely. Customer action: Required.

Details

Security updates
10.0.26300.9711 — https://support.microsoft.com/help/5127648
10.0.17763.9376 — https://support.microsoft.com/help/5126651
10.0.20348.5761 — https://support.microsoft.com/help/5126655
10.0.19044.7807 — https://support.microsoft.com/help/5126657
10.0.26100.33650 — https://support.microsoft.com/help/5126646
10.0.22631.7652 — https://support.microsoft.com/help/5126653
10.0.28000.3231 — https://support.microsoft.com/help/5127646
10.0.14393.9612 — https://support.microsoft.com/help/5126868

Vulnerabilities 1

Medium 6.5

CVE-2026-83649

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

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

Microsoft Windows Server 2019 Windows Server 2019 (Server Core installation) Windows 10 Version 1809 Windows

Oct 13, 2026

Revision history

2026-10-13 #1
Information published.

References

CVE-2026-83649 Windows Local Security Authority Subsystem Service (LSASS) Denial of Service Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-83649
Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
Common Vulnerability Scoring System
https://www.first.org/cvss