Heap-based buffer overflow in Microsoft Windows and Windows Server - CVE-2026-65786

Vulnerability identifier: #VU141812

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-2026-65786

CWE-ID: CWE-122

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to elevate privileges.

The vulnerability exists due to heap-based buffer overflow in Desktop Window Manager when handling local input. A local user can trigger the overflow to elevate privileges.

Successful exploitation could lead to SYSTEM privileges.

Microsoft Windows
Windows Server

Install security update 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://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-65786
• https://support.microsoft.com/help/5120238

• Multiple vulnerabilities in Microsoft Windows