CVE-2017-18078

Exp

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.

Published: 2018-01-29 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-18078 is rated High Exploit Risk (68.5/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.08%). 5 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2017-18078

EDB-ID Source Kind Published Link
43935 exploit_db edb 2018-01-29 Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2017-18078

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.11% 1.08% +0.98%
2 2025-07-12 0.18% 0.11% -0.07%
3 2025-03-30 — 0.18% —

Full EPSS history (10 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-18078

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.8 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 1.8 5.9 [email protected]
4.6 2.0 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 3.9 6.4 [email protected]

Weakness enumeration for CVE-2017-18078

OS Trackers for CVE-2017-18078

vendor priority summary link
debian unimportant CVE-2017-18078 unimportant priority: Debian including 1 source packages (systemd), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-18078
redhat medium — https://access.redhat.com/security/cve/CVE-2017-18078
suse high CVE-2017-18078 severity important: SUSE including 524 source package names (0.9.1:libsystemd0-228-150.32.1, 0.9.1:libudev1-228-150.32.1, …), 748 product×package rows across 69 product lines (Container caasp/v4/default-http-backend, Container caasp/v4/dnsmasq-nanny, … (69 product lines)): Fixed 480, Known Affected 157, Known Not Affected 111. https://www.suse.com/security/cve/CVE-2017-18078/
ubuntu low CVE-2017-18078 low priority: Ubuntu including 1 source packages (systemd), 4 status rows across 4 suites (artful, trusty, upstream, xenial): ignored 3, needs-triage 1. https://ubuntu.com/security/CVE-2017-18078

Affected software / configurations for CVE-2017-18078

Vendor Product Version Raw CPE
systemd_project systemd < 237 cpe:2.3:a:systemd_project:systemd:*:*:*:*:*:*:*:*
debian debian_linux 8.0 cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*
opensuse leap 42.3 cpe:2.3:o:opensuse:leap:42.3:*:*:*:*:*:*:*

References for CVE-2017-18078

URL Tags
http://lists.opensuse.org/opensuse-updates/2018-02/msg00109.html Mailing List Third Party Advisory
http://packetstormsecurity.com/files/146184/systemd-Local-Privilege-Escalation.html Exploit Third Party Advisory VDB Entry
http://www.openwall.com/lists/oss-security/2018/01/29/3 Exploit Mailing List Third Party Advisory
https://github.com/systemd/systemd/issues/7736 Exploit Issue Tracking Third Party Advisory
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://lists.debian.org/debian-lts-announce/2019/04/msg00022.html Mailing List Third Party Advisory
https://www.exploit-db.com/exploits/43935/ Exploit Third Party Advisory VDB Entry
https://www.openwall.com/lists/oss-security/2018/01/29/4 Mailing List Third Party Advisory
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