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.
The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.