CVE-2018-6558

The pam_fscrypt module in fscrypt before 0.2.4 may incorrectly restore primary and supplementary group IDs to the values associated with the root user, which allows attackers to gain privileges via a successful login through certain applications that use Linux-PAM (aka pam).

Published: 2018-08-23 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-6558 is rated Moderate Risk (42.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.62%). 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-2018-6558

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 0.14% 0.62% +0.48%
2 2026-02-16 0.22% 0.14% -0.07%
3 2025-03-30 — 0.22% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-6558

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N 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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]
4.9 2.0 MEDIUM
AV:N/AC:M/Au:S/C:N/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:S)
A single authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 6.8 4.9 [email protected]

Weakness enumeration for CVE-2018-6558

GitHub Security Advisory for CVE-2018-6558

OS Trackers for CVE-2018-6558

vendor priority summary link
debian not yet assigned CVE-2018-6558 not yet assigned priority: Debian including 1 source packages (fscrypt), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2018-6558
ubuntu medium CVE-2018-6558 medium priority: Ubuntu including 1 source packages (fscrypt), 6 status rows across 6 suites (bionic, cosmic, disco, trusty, upstream, xenial): DNE 2, ignored 1, needed 1, not-affected 1, released 1. https://ubuntu.com/security/CVE-2018-6558

Affected software / configurations for CVE-2018-6558

Vendor Product Version Raw CPE
google fscrypt < 0.2.4 cpe:2.3:a:google:fscrypt:*:*:*:*:*:*:*:*

References for CVE-2018-6558

cvelogic Threat Intelligence