CVE-2018-6954

Published: 13 February 2018

systemd-tmpfiles in systemd through 237 mishandles symlinks present in non-terminal path components, which allows local users to obtain ownership of arbitrary files via vectors involving creation of a directory and a file under that directory, and later replacing that directory with a symlink. This occurs even if the fs.protected_symlinks sysctl is turned on.

Priority

Medium

CVSS 3 base score: 7.8

Status

Package Release Status
systemd
Launchpad, Ubuntu, Debian
Upstream Needs triage

Ubuntu 18.04 LTS (Bionic Beaver)
Released (237-3ubuntu10.9)
Ubuntu 16.04 LTS (Xenial Xerus)
Released (229-4ubuntu21.15)
Ubuntu 14.04 ESM (Trusty Tahr) Not vulnerable
(binary not built)
Patches:
Upstream: https://github.com/systemd/systemd/pull/8358
Upstream: https://github.com/systemd/systemd/pull/8822
Upstream: https://github.com/systemd/systemd/commit/936f6bdb803c432578e2cdcc5f93f3bfff93aff0

Notes

AuthorNote
mdeslaur original fix was incomplete, see second pull
chrisccoulson Fix reverted in xenial because it breaks containers running on pre-2.6.39 kernels
mdeslaur fix was re-introduced in xenial in 229-4ubuntu21.15

References

Bugs