CVE-2018-12027

An Insecure Permissions vulnerability in SpawningKit in Phusion Passenger 5.3.x before 5.3.2 causes information disclosure in the following situation: given a Passenger-spawned application process that reports that it listens on a certain Unix domain socket, if any of the parent directories of said socket are writable by a normal user that is not the application's user, then that non-application user can swap that directory with something else, resulting in traffic being redirected to a non-application user's process through an alternative Unix domain socket.

Published: 2018-06-17 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-12027 is rated Moderate Risk (57.3/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.09%). Review affected assets and schedule remediation.

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

Exploit prediction scoring system (EPSS) score for CVE-2018-12027

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 0.29% 1.09% +0.80%
2 2025-03-30 0.92% 0.29% -0.63%
3 2025-03-29 — 0.92% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-12027

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
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.
 2.8 5.9 [email protected]
6.5 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 6.4 [email protected]

Weakness enumeration for CVE-2018-12027

GitHub Security Advisory for CVE-2018-12027

GHSA-whfx-877c-5p28 · Severity: high · Ecosystem: rubygems — Insecure Permissions in Phusion Passenger

OS Trackers for CVE-2018-12027

vendor priority summary link
debian unimportant CVE-2018-12027 unimportant priority: Debian including 1 source packages (passenger), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-12027
gentoo normal CVE-2018-12027: 1 GLSA(s) (201807-02), 1 atom(s) (www-apache/passenger); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2018-12027
redhat medium — https://access.redhat.com/security/cve/CVE-2018-12027
ubuntu medium CVE-2018-12027 medium priority: Ubuntu including 2 source packages (passenger, ruby-passenger), 26 status rows across 13 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial): DNE 13, ignored 6, not-affected 5, needs-triage 1, released 1. https://ubuntu.com/security/CVE-2018-12027

Affected software / configurations for CVE-2018-12027

Vendor Product Version Raw CPE
phusion passenger >= 5.3.0, < 5.3.2 cpe:2.3:a:phusion:passenger:*:*:*:*:*:*:*:*

References for CVE-2018-12027

URL Tags
https://blog.phusion.nl/passenger-5-3-2 Mitigation Vendor Advisory
https://security.gentoo.org/glsa/201807-02 Third Party Advisory
cvelogic Threat Intelligence