Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-69594
Published: September 8, 2026
Vulnerability identifier: #VU147828
CSH Severity: Low
CVSS v4: 8.5 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-69594
CWE-ID: CWE-122
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to a heap-based buffer overflow in Microsoft Local Security Authority Server (lsasrv) when processing local input. A local user can exploit the buffer overflow to escalate privileges.
Successful exploitation can grant SYSTEM privileges.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-69594
Install security update from vendor's website.
Microsoft Windows - addressed in versions 11 24H2 10.0.26100.9445, 11 25H2 10.0.26200.9445, 11 26H1 10.0.28000.2954
Windows Server - update to 2025 10.0.26100.33438
Windows Server - update to 2025 10.0.26100.33438