The AhcVerifyAdminContext function in ahcache.sys in the Application Compatibility component in Microsoft Windows 7 SP1, Windows Server 2008 R2 SP1, Windows 8, Windows 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 does not verify that an impersonation token is associated with an administrative account, which allows local users to gain privileges by running AppCompatCache.exe with a crafted DLL file, aka MSRC ID 20544 or "Microsoft Application Compatibility Infrastructure Elevation of Privilege Vulnerability."