Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-69563
Published: September 8, 2026
Vulnerability identifier: #VU147798
CSH Severity: Low
CVSS v4: 7.3 [CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-69563
CWE-ID: CWE-122
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to elevate privileges.
The vulnerability exists due to a heap-based buffer overflow in the Windows Program Compatibility Assistant Service when the service is accessed locally. A local user can exploit the vulnerability to elevate privileges.
Successful exploitation requires winning a race condition and can result in SYSTEM privileges.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-69563
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7725, 10 22H2 10.0.19045.7725, 10 1607 10.0.14393.9512, 10 1809 10.0.17763.9245, 11 23H2 10.0.22631.7582, 11 24H2 10.0.26100.9445, 11 25H2 10.0.26200.9445, 11 26H1 10.0.28000.2954
Windows Server - addressed in versions 2016 10.0.14393.9512, 2019 10.0.17763.9245, 2022 10.0.20348.5622, 2025 10.0.26100.33438
Windows Server - addressed in versions 2016 10.0.14393.9512, 2019 10.0.17763.9245, 2022 10.0.20348.5622, 2025 10.0.26100.33438