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, R2, and R2 SP1, Windows 7 Gold and SP1, and Windows 8 Consumer Preview does not properly handle user-mode input passed to kernel mode, which allows local users to gain privileges via a crafted application, aka "Scrollbar Calculation Vulnerability."
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A15555
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-034
http://www.us-cert.gov/cas/techalerts/TA12-129A.html