win32k.sys in the kernel-mode drivers 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 allows local users to gain privileges via a crafted application, aka "Win32k Elevation of Privilege Vulnerability."
https://www.exploit-db.com/exploits/38266/
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2015/ms15-073