Integer underflow in Microsoft Windows and Windows Server - CVE-2026-62696

Vulnerability identifier: #VU141592

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-2026-62696

CWE-ID: CWE-191

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges on the target system.

The vulnerability exists due to integer underflow in Windows Program Compatibility Assistant Service. A local user can send trigger integer underflow and gain elevated privileges on the system.

Microsoft Windows
Windows Server

Install updates from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7663, 10 22H2 10.0.19045.7663, 10 1607 10.0.14393.9418, 10 1809 10.0.17763.9115, 11 23H2 10.0.22631.7517, 11 24H2 10.0.26100.9106, 11 24H2 10.0.26100.9168, 11 25H2 10.0.26200.9168, 11 26H1 10.0.28000.2704
Windows Server - addressed in versions 2016 10.0.14393.9418, 2019 10.0.17763.9115, 2022 10.0.20348.5440, 2022 10.0.20348.5499, 2025 10.0.26100.33222, 2025 10.0.26100.33296

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-62696

• Privilege escalation in Microsoft Windows Program Compatibility Assistant Service