Out-of-bounds read in Microsoft Windows and Windows Server - CVE-2026-26155

Vulnerability identifier: #VU126061

CSH Severity: Medium

CVSS v4: 7.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]

CVE-ID: CVE-2026-26155

CWE-ID: CWE-125

Exploitation vector: Remote access

Exploit availability: No public exploit available

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition in Microsoft Local Security Authority Subsystem Service. A remote 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 10.0.19044.7184, 10 22H2 10.0.19045.7184, 10 1607 10.0.14393.9060, 10 1809 10.0.17763.8644, 11 23H2 10.0.22631.6936, 11 24H2 10.0.26100.32690, 11 25H2 10.0.26200.8246, 11 26H1 10.0.28000.1836
Windows Server - addressed in versions 2012 R2 6.3.9600.23132, 2016 10.0.14393.9060, 2019 10.0.17763.8644, 2022 23H2 10.0.25398.2274, 2022 10.0.20348.5020, 2025 10.0.26100.32690

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26155

• Information disclosure in Microsoft Local Security Authority Subsystem Service