DescriptionThe fs_pin implementation in the Linux kernel before 4.0.5 does not ensure the internal consistency of a certain list data structure, 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, related to fs/fs_pin.c and include/linux/fs_pin.h.
SourceCVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)buster4.19.249-2fixed
buster (security)4.19.304-1fixed
bullseye (security)5.10.216-1fixed
bookworm (security)6.1.90-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsource(unstable)(not affected)
linux-2.6source(unstable)(not affected)


- 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: (v4.1-rc1)
Fixed by: (v4.1-rc1)

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