Windows Server 2016 EUVD-2026-22451

Local system access as authenticated user required. Windows User Interface Core must process concurrent requests on shared resources without proper synchronization. High attack complexity due to race condition timing requirements.

Real-world risk is moderate-to-high for privileged endpoint environments. CVSS 7.8 reflects local attack vector requiring low privileges (PR:L) but high attack complexity (AC:H), indicating successful exploitation demands precise timing manipulation. The scope change (S:C) confirms privilege boundary escape from user to SYSTEM context. EPSS data not provided, but race condition exploitation historically requires specialized tooling and system-specific tuning, reducing mass exploitation likelihood compared to memory corruption flaws. No confirmed actively exploited (CISA KEV) status and no public exploit identified at time of analysis lower immediate urgency. However, the comprehensive version coverage (all supported Windows client/server OS) and potential for lateral movement post-compromise in enterprise networks elevate priority. Patch available per vendor advisory mitigates deployment friction. Organizations should prioritize patching on high-value assets, privileged access workstations, and multi-tenant systems where local user accounts exist. The AC:H rating suggests automated exploitation at scale is unlikely, favoring targeted manual attacks.

An attacker with standard user credentials on a corporate Windows 10 workstation executes a custom exploit tool that rapidly creates and destroys UI window objects while monitoring kernel object handles. By precisely timing thread execution to exploit the race window in User Interface Core's synchronization logic, the attacker manipulates the UI subsystem to assign SYSTEM-level privileges to their user session token during a state transition. With