win32k.sys in the kernel-mode drivers in Microsoft Windows XP SP2 and SP3, Windows Server 2003 SP2, Windows Vista SP2, Windows Server 2008 SP2 and R2 SP1, Windows 7 SP1, Windows 8, Windows Server 2012, and Windows RT does not properly handle objects in memory, which allows local users to gain privileges via a crafted application, aka "Win32k Window Handle Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16091
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2013/ms13-046