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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.

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
Priority

Medium

CVSS 3 base score: 7.8

Status

Package Release Status
systemd
Launchpad, Ubuntu, Debian
artful Ignored
(reached end-of-life)
bionic
Released (237-3ubuntu10.9)
cosmic
Released (239-7ubuntu10.4)
precise Does not exist

trusty Not vulnerable
(binary not built)
upstream Needs triage

xenial
Released (229-4ubuntu21.15)
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