Inclusion of Functionality from Untrusted Control Sphere in Microsoft Windows and Windows Server - CVE-2026-85355

Vulnerability identifier: #VU155118

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-2026-85355

CWE-ID: CWE-829

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local user to escalate privileges to SYSTEM.

The vulnerability exists due to inclusion of functionality from an untrusted control sphere in the Windows Common Log File System Driver when incorporating untrusted functionality. A local user can win a race condition to escalate privileges to SYSTEM.

Microsoft Windows
Windows Server

Install security update from vendor's website.

Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7807, 10 1607 10.0.14393.9612, 10 1809 10.0.17763.9376, 11 23H2 10.0.22631.7652, 11 24H2 10.0.26100.9711, 11 25H2 10.0.26200.9711, 11 26H1 10.0.28000.3231
Windows Server - addressed in versions 2012 R2 6.3.9600.23470, 2012 6.2.9200.26434, 2016 10.0.14393.9612, 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-85355

• Multiple vulnerabilities in Microsoft Windows