What is CVE-2018-6954?

CVE-2018-6954 is a high-severity vulnerability in Systemd Project, classified under Improper Link Resolution Before File Access. CVSS score: 7.8/10. Published 2018-02-13.

How severe is CVE-2018-6954?

High severity. CVSS v3 base score is 7.8 out of 10.

Is CVE-2018-6954 known to be exploited?

6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

Vulnerability in Systemd Project

CVE-2018-6954

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.

Published 2018-02-13 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.005 (43.3th percentile), scored 2026-10-20.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 43rd percentile — 43.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: 0.000

Affected products

Systemd Project
Canonical Ubuntu Linux — versions 16.04, 18.04, 18.10
openSUSE Leap — versions 42.3

Weakness classification (CWE)

CWE-59 — Improper Link Resolution Before File Access

Public proof-of-concept exploits

References

usn.ubuntu.com/3816-2/ (vendor-advisory, Third Party Advisory)
github.com/systemd/systemd/issues/7986 (Exploit, Patch, Third Party Advisory, Issue Tracking)
usn.ubuntu.com/3816-1/ (vendor-advisory, Third Party Advisory)
lists.opensuse.org/opensuse-security-announce/2019-05/msg00062.html (vendor-advisory, Third Party Advisory)
lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a4508… (mailing-list)
lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698… (mailing-list)

Frequently asked questions

What is CVE-2018-6954?: CVE-2018-6954 is a high-severity vulnerability in Systemd Project, classified under Improper Link Resolution Before File Access. CVSS score: 7.8/10. Published 2018-02-13.
How severe is CVE-2018-6954?: High severity. CVSS v3 base score is 7.8 out of 10.
Is CVE-2018-6954 known to be exploited?: 6 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.