CVE-2018-6558
Privilege Escalation in fscrypt
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).
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
NVD Score used
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).
- Record
CVE-2018-6558- CVSS 3.0
- 6.5 Medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - CVSS 2.0
- 4.9 Medium
AV:N/AC:M/Au:S/C:N/I:P/A:P - Updated
- 2026-11-02
CVE List No score
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).
- Record
CVE-2018-6558- Updated
- 2026-11-02
EUVDEUVD-2021-1381 No score
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).
- Record
EUVD-2021-1381- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-qj26-7grj-whg3
Privilege Escalation in fscrypt
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).
- Record
GHSA-qj26-7grj-whg3- CVSS 3.0
- 6.5 Medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSV
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).
- Record
CVE-2018-6558- CVSS 3.0
- 6.5 Medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVDEBIAN-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).
- Record
DEBIAN-CVE-2018-6558- CVSS 3.0
- 6.5 Medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVGHSA-qj26-7grj-whg3
Privilege Escalation in fscrypt
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).
- Record
GHSA-qj26-7grj-whg3- CVSS 3.0
- 6.5 Medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-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).
- Record
UBUNTU-CVE-2018-6558- CVSS 3.0
- 6.5 Medium
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N - Updated
- 2026-11-02
OSVGO-2020-0027 No score
Privilege escalation in github.com/google/fscrypt
After dropping and then elevating process privileges euid, guid, and groups are not properly restored to their original values, allowing an unprivileged user to gain membership in the root group.
- Record
GO-2020-0027- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
github.com/google/fscryptGo |
before 0.2.4 | 0.2.4 |
fscryptDebian:12 |
before 0.2.4-1 | 0.2.4-1 |
fscryptDebian:13 |
before 0.2.4-1 | 0.2.4-1 |
fscryptDebian:14 |
before 0.2.4-1 | 0.2.4-1 |
fscryptUbuntu:18.04:LTS |
before 0.2.2-0ubuntu2.1, plus listed versions 0.2.2-0ubuntu2 |
0.2.2-0ubuntu2.1 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases, products | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2018-6558 is a medium vulnerability (CVSS 6.5) in Google Fscrypt, published August 23, 2018. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.62%, the 50th percentile. Fixed in github.com/google/fscrypt 0.2.4.