The kernel-mode driver in Microsoft Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 does not properly constrain impersonation levels, which allows local users to gain privileges via a crafted application, aka "Windows KMD Security Feature Bypass Vulnerability."