system
Describe <CVE-2015-4177>.
user
What is <CVE-2015-4177>?
assistant
The collect_mounts function in fs/namespace.c in the Linux kernel before 4.0.5 does not properly consider that it may execute after a path has been unmounted, which allows local users to cause a denial of service (system crash) by leveraging user-namespace root access for an MNT_DETACH umount2 system call..