Out-of-bounds read in Microsoft Windows and Windows Server - CVE-2026-34336

Vulnerability identifier: #VU131243

CSH Severity: Low

CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-34336

CWE-ID: CWE-125

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition in Windows DWM Core Library. A local user can trigger an out-of-bounds read error and read contents of memory on the system.

Microsoft Windows
Windows Server

Install updates from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7291, 10 22H2 10.0.19045.7291, 10 1607 10.0.14393.9140, 10 1809 10.0.17763.8755, 11 23H2 10.0.22631.7079, 11 24H2 10.0.26100.8390, 11 24H2 10.0.26100.8457, 11 25H2 10.0.26200.8390, 11 25H2 10.0.26200.8457, 11 26H1 10.0.28000.2113
Windows Server - addressed in versions 2016 10.0.14393.9140, 2019 10.0.17763.8755, 2022 23H2 10.0.25398.2330, 2022 10.0.20348.5074, 2022 10.0.20348.5139, 2025 10.0.26100.32772, 2025 10.0.26100.32860

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-34336

• Multiple vulnerabilities in Microsoft Windows DWM Core Library