The NVIDIA drivers provide support for NVIDIA graphic boards.
Gregory Shikhman discovered that the default Gentoo setup of NVIDIA drivers creates the /dev/nvidia* with insecure file permissions.
A local attacker could send arbitrary values into the devices, possibly resulting in hardware damage on the graphic board or a Denial of Service.
There is no known workaround at this time.
All NVIDIA drivers users should upgrade to the latest version:
# emerge --sync
# emerge --ask --oneshot --verbose "x11-drivers/nvidia-drivers"