CVE-2018-12557: An issue was discovered in Zuul 3.x before 3.1.0

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CRITICAL 9.8REMOTEUPGRADE

CVE-2018-12557 is a critical-severity flaw (CVSS 9.8) affecting zuul. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Zuul 3.x before 3.1.0. If nodes become offline during the build, the no_log attribute of a task is ignored. If the unreachable error occurred in a task used with a loop variable (e.g., with_items), the contents of the loop items would be printed in the console. This could lead to accidentally leaking credentials or secrets.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.9% (top 21%)
CISA exploited list	No
Weakness	CWE-200
Published	2018-06-19
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: zuul-ci

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-06-19 05:29 UTCPublished CVE record published
2026-06-17 01:37 UTCUpdated Record last modified

zuul-ci zuul UPGRADE

Affected: >= 3.0.0 and < 3.1.0

Fixed in: 3.1.0

Safe to downgrade to: a release before 3.0.0

1. Check installed version

apt-cache policy zuul || rpm -q zuul || zuul --version

2. UPGRADE to 3.1.0 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade zuul

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade zuul

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 3.0.0 (Debian / Ubuntu)

apt-cache madison zuul sudo apt install zuul=<VERSION_BEFORE_3.0.0> sudo apt-mark hold zuul

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list zuul sudo dnf downgrade zuul-<VERSION_BEFORE_3.0.0> sudo dnf versionlock add zuul

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-12557?

zuul: upgrade to 3.1.0. Exact commands for each OS are on this page.

Is CVE-2018-12557 being exploited?

CVE-2018-12557 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-12557 affect?

CVE-2018-12557 affects zuul. Severity is critical (CVSS 9.8). An issue was discovered in Zuul 3.x before 3.1.0. If nodes become offline during the build, the no_log attribute of a task is ignored. If the unreachable error occurred in a task used with a loop variable (e.g., with_items), the contents of

How urgent is CVE-2018-12557?

Priority 59/100. Critical severity; Remotely exploitable, no login, no user action

References

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