Use-after-free in Microsoft Windows and Windows Server - CVE-2026-83901
Published: October 14, 2026
Vulnerability identifier: #VU155044
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-2026-83901
CWE-ID: CWE-416
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 use-after-free in the Windows Win32 Kernel Subsystem when the subsystem is used locally. A local user can exploit this memory management flaw to escalate privileges to SYSTEM.
Successful exploitation requires specific conditions, such as particular protocol settings or configurations, to be in place.
Affected software
Microsoft Windows
Windows Server
Windows Server
How to mitigate CVE-2026-83901
Install security update from vendor's website.
Microsoft Windows - addressed in versions 10 21H2 10.0.19044.7807, 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 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650
Windows Server - addressed in versions 2019 10.0.17763.9376, 2022 10.0.20348.5761, 2025 10.0.26100.33650