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 8.1, Windows Server 2012 Gold and R2, and Windows RT Gold and 8.1 allows local users to obtain sensitive information from kernel memory or cause a denial of service (system hang) via a crafted application, aka "Win32k Information Disclosure Vulnerability."
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-015