Out-of-bounds read in Microsoft Windows and Windows Server - CVE-2026-85858
Published: October 14, 2026
Vulnerability identifier: #VU155201
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-2026-85858
CWE-ID: CWE-125
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to escalate privileges to SYSTEM.
The vulnerability exists due to an out-of-bounds read in the Windows Win32 Kernel Subsystem when a race condition is triggered. A local user can win the race condition to escalate privileges to SYSTEM.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-85858
Install security update from vendor's website.
Microsoft Windows - addressed in versions 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 2022 10.0.20348.5761, 2025 10.0.26100.33650
Windows Server - addressed in versions 2022 10.0.20348.5761, 2025 10.0.26100.33650