"Arbitrary code execution, potentially in the kernel".
Luckily, the kernel component of graphics drivers (at least the NVIDIA one) is comparatively small these days, and mainly concerns memory/buffer allocation and resource scheduling. Apart from that, it provides a memory-mapped command queue directly to the GPU. Memory protection is enforced in hardware.
The user-space part of the driver, on the other hand, is the complex beast that handles all the GL rendering commands. It's much more likely that an exploit would happen there (still not good, but heh it sounds less scary and can be controlled with user-space security restrictions).
Luckily, the kernel component of graphics drivers (at least the NVIDIA one) is comparatively small these days, and mainly concerns memory/buffer allocation and resource scheduling. Apart from that, it provides a memory-mapped command queue directly to the GPU. Memory protection is enforced in hardware.
The user-space part of the driver, on the other hand, is the complex beast that handles all the GL rendering commands. It's much more likely that an exploit would happen there (still not good, but heh it sounds less scary and can be controlled with user-space security restrictions).