|Description||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.|
|Source||CVE (at NVD; CERT, LWN, oss-sec, fulldisc, bugtraq, EDB, Metasploit, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, Mageia, GitHub code/issues, web search, more)|
|NVD severity||medium (attack range: local)|
Vulnerable and fixed packages
The table below lists information on source packages.
|stretch (security), stretch||4.9.82-1+deb9u3||fixed|
The information below is based on the following data on fixed versions.
|Package||Type||Release||Fixed Version||Urgency||Origin||Debian Bugs|
- linux <not-affected> (Commit was applied to 4.0.2 as well but fixed in Debian by two subsequent commits)
Debian both applies "mnt: Fail collect_mounts when applied to unmounted mounts"
and "fs_pin: Allow for the possibility that m_list or s_list go unused." in
- linux-2.6 <not-affected> (Introduced and fixed in 4.1-rc1 upstream)
Introduced by: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=ce07d891a0891d3c0d0c2d73d577490486b809e1 (v4.1-rc1)
Fixed by: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=cd4a40174b71acd021877341684d8bb1dc8ea4ae (v4.1-rc1)