CVE-2017-18078

Name	CVE-2017-18078
Description	systemd-tmpfiles in systemd before 237 attempts to support ownership/permission changes on hardlinked files even if the fs.protected_hardlinks sysctl is turned off, which allows local users to bypass intended access restrictions via vectors involving a hard link to a file for which the user lacks write access, as demonstrated by changing the ownership of the /etc/passwd file.
Source	CVE (at NVD; CERT, LWN, oss-sec, fulldisc, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
References	DLA-1762-1

Vulnerable and fixed packages

The table below lists information on source packages.

Source Package	Release	Version	Status
systemd (PTS)	bullseye	247.3-7+deb11u5	fixed
	bookworm	252.26-1~deb12u2	fixed
	trixie	256.2-1	fixed
	sid	256.4-2	fixed

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

Package	Type	Release	Fixed Version	Urgency	Origin	Debian Bugs
systemd	source	jessie	215-17+deb8u12		DLA-1762-1
systemd	source	(unstable)	237-1	unimportant

Notes

https://github.com/systemd/systemd/issues/7736
https://github.com/systemd/systemd/commit/5579f85663d10269e7ac7464be6548c99cea4ada (v237)
Neutralised by kernel hardening