CVE-2018-6954
CVE-2018-6954 is a high-severity vulnerability in Systemd Project Systemd with a CVSS 3.x base score of 7.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-59.
Key facts
- Severity: High (CVSS 3.x base score 7.8)
- CVSS v2: 7.2
- EPSS exploit prediction: 1% (41st percentile)
- Actively exploited: Not listed in CISA KEV
- Weakness: CWE-59
- Affected product: Systemd Project Systemd
- Published:
- Last modified:
Description
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.
Frequently asked questions
- What is 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.
- How severe is CVE-2018-6954?
- CVE-2018-6954 has a CVSS 3.x base score of 7.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2018-6954 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (41st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2018-6954?
- CVE-2018-6954 primarily affects Systemd Project Systemd. In total, 5 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2018-6954?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2018-6954 published?
- CVE-2018-6954 was published on 2018-02-13 and last updated on 2026-06-17.
References
- http://lists.opensuse.org/opensuse-security-announce/2019-05/msg00062.html
- https://github.com/systemd/systemd/issues/7986
- https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E
- https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E
- https://usn.ubuntu.com/3816-1/
- https://usn.ubuntu.com/3816-2/
Affected products (5)
- cpe:2.3:a:systemd_project:systemd:*:*:*:*:*:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:16.04:*:*:*:lts:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:18.04:*:*:*:lts:*:*:*
- cpe:2.3:o:canonical:ubuntu_linux:18.10:*:*:*:*:*:*:*
- cpe:2.3:o:opensuse:leap:42.3:*:*:*:*:*:*:*
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