The nvCommandQueue::GetHandleIndex method in the NVIDIA Graphics Drivers subsystem in Apple OS X before 10.11.5 allows attackers to execute arbitrary code in a privileged context or cause a denial of service (NULL pointer dereference and memory corruption) via a crafted app.
https://www.exploit-db.com/exploits/39920/
https://support.apple.com/HT206567
https://bugs.chromium.org/p/project-zero/issues/detail?id=784
http://www.securitytracker.com/id/1035895
http://www.securityfocus.com/bid/90696
http://packetstormsecurity.com/files/137403/OS-X-GeForce.kext-NULL-Pointer-Dereference.html
http://lists.apple.com/archives/security-announce/2016/May/msg00004.html