The NVIDIA Display Driver R304 before 309.08, R340 before 341.44, R343 before 345.20, and R346 before 347.52 does not properly validate local client impersonation levels when performing a "kernel administrator check," which allows local users to gain administrator privileges via unspecified API calls.
https://support.lenovo.com/us/en/product_security/nvidia_windows_privilege
https://support.lenovo.com/product_security/nvidia_windows_privilege
http://www.securitytracker.com/id/1032013
http://nvidia.custhelp.com/app/answers/detail/a_id/3634