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Fencer Intel
low 3.5

CVE-2026-3254 json

Improper Restriction of Rendered UI Layers or Frames in GitLab

published 6mo ago modified 4mo ago also BIT-gitlab-2026-3254 , EUVD-2026-24961

cvss
3.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.2%
EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits
0
none known

Summary

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.

Patch / fix

  • bitnami gitlab 18.11.1
  • GitLab GitLab 18.11.1

Is CVE-2026-3254 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

Check with Fencer

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
6mo ago

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • hackerone.com https://hackerone.com/reports/3572752 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
OSV 3.1 3.5 CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

Affected packages

ecosystem package affected fixed in
bitnami gitlab
>=18.11.0, <18.11.1
18.11.1

Affected products

  • GitLab GitLab

Classification

Weakness
  • CWE-1021 Improper Restriction of Rendered UI Layers or Frames
Technology feeds

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.