An issue was discovered in drivers/media/platform/vivid in the Linux kernel
through 5.3.8. It is exploitable for privilege escalation on some Linux
distributions where local users have /dev/video0 access, but only if the
driver happens to be loaded. There are multiple race conditions during
streaming stopping in this driver (part of the V4L2 subsystem). These
issues are caused by wrong mutex locking in
vivid_stop_generating_vid_cap(), vivid_stop_generating_vid_out(),
sdr_cap_stop_streaming(), and the corresponding kthreads. At least one of
these race conditions leads to a use-after-free.

It was discovered that a race condition existed in the Virtual Video Test
Driver in the Linux kernel. An attacker with write access to /dev/video0 on
a system with the vivid module loaded could possibly use this to gain
administrative privileges.

tyhicks

This rarely used driver module cannot be loaded by an unprivileged user so the impact is lessened