win32k.sys in the kernel-mode drivers in Microsoft Windows Vista SP2, Windows Server 2008 SP2, R2, and R2 SP1, Windows 7 Gold and SP1, Windows 8, Windows Server 2012, and Windows RT does not properly handle window broadcast messages, which allows local users to gain privileges via a crafted application, aka "Win32k Improper Message Handling Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16326
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2013/ms13-005
http://www.us-cert.gov/cas/techalerts/TA13-008A.html