CVE-2026-3254: GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.11 before 18.11.1 that under cer

Routine

LOW 3.5DOWNGRADE

CVE-2026-3254 is a low-severity flaw (CVSS 3.5) affecting gitlab. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.11 before 18.11.1 that under certain conditions could have allowed an authenticated user to load unauthorized content into another user's browser due to improper input validation in the Mermaid sandbox.

Why this priority

No elevated risk signals yet

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	3.5 (Low)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 96%)
CISA exploited list	No
Weakness	CWE-1021
Published	2026-04-22
Last modified	2026-06-17

Publisher (CNA): GitLab Inc. · Vendor: gitlab

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

Am I affected?

Timeline

2026-04-22 17:16 UTCPublished CVE record published
2026-06-17 10:43 UTCUpdated Record last modified

gitlab gitlab DOWNGRADE

Affected: 18.11.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 18.11.0

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 18.11.0 (Debian / Ubuntu)

apt-cache madison gitlab sudo apt install gitlab=<VERSION_BEFORE_18.11.0> sudo apt-mark hold gitlab

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list gitlab sudo dnf downgrade gitlab-<VERSION_BEFORE_18.11.0> sudo dnf versionlock add gitlab

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-2026-3254?

gitlab: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-3254 being exploited?

CVE-2026-3254 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-2026-3254 affect?

CVE-2026-3254 affects gitlab. Severity is low (CVSS 3.5). GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.11 before 18.11.1 that under certain conditions could have allowed an authenticated user to load unauthorized content into another user's browser due to improper

How urgent is CVE-2026-3254?

Priority 13/100. No elevated risk signals yet.

Software pages

GitLab vulnerabilities

Related CVEs

CVE-2026-15723 HIGH 8.2 UPGRADE GitLab has remediated an issue in GitLab CE/EE affecting all versions from 10.1 before 19.3.6, 19.4 before 19.
CVE-2026-13319 MEDIUM 4.3 UPGRADE GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.10 before 19.3.6, 19.4 before 19
CVE-2026-12664 MEDIUM 6.8 UPGRADE GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.2 before 19.3.6, 19.4 before 19.
CVE-2026-112326 LOW 3.1 UPGRADE GitLab has remediated an issue in GitLab EE affecting all versions from 17.8 before 19.3.6, 19.4 before 19.4.3
CVE-2026-112212 HIGH 7.5 UPGRADE GitLab has remediated an issue in GitLab CE/EE affecting all versions from 18.3 before 19.3.6, 19.4 before 19.

References

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