CVE-2018-15687: systemd: chown_one() can dereference symlinks

Severity: high (CVSS 7.0 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2018-10-26 · updated 2026-06-17
Weakness: CWE-362

Description

A race condition in chown_one() of systemd allows an attacker to cause systemd to set arbitrary permissions on arbitrary files. Affected releases are systemd versions up to and including 239.

Affected products

Canonical Ubuntu Linux: 16.04, 18.04, 18.10
systemd: from 235 before 240 — fixed in 240

How to fix

Upgrade to a fixed version: systemd 240. Check the vendor advisory for mitigations.

References

http://www.securityfocus.com/bid/105748
https://github.com/systemd/systemd/pull/10517/commits
https://security.gentoo.org/glsa/201810-10
https://usn.ubuntu.com/3816-1/
https://www.exploit-db.com/exploits/45715/
http://www.securityfocus.com/bid/105748
https://github.com/systemd/systemd/pull/10517/commits
https://security.gentoo.org/glsa/201810-10
https://usn.ubuntu.com/3816-1/
https://www.exploit-db.com/exploits/45715/

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