Double free vulnerability in the Ancillary Function Driver (AFD) in afd.sys in the kernel-mode drivers in Microsoft 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 gain privileges via a crafted application, aka "Ancillary Function Driver Elevation of Privilege Vulnerability."
https://www.exploit-db.com/exploits/39525/
https://www.exploit-db.com/exploits/39446/
https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-040
http://www.zerodayinitiative.com/advisories/ZDI-14-220/