Vulnerability · Published Apr 22, 2026 · Assigned by GitLab
CVE-2026-3254Improper Restriction of Rendered UI Layers or Frames in GitLab
Low 3.5
In plain English
A low-severity security flaw in GitLab from GitLab. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 4% of all known vulnerabilities).
Severity (CVSS 3.1)3.5Low
Exploit odds (30 days)0.2%top 95.6% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
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.
Affected products (as reported)
Weakness: CWE-1021 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
References
- HackerOne Bug Bounty Report #3572752 technical-description, exploit, permissions-required
- https://gitlab.com/gitlab-org/gitlab/-/work_items/591587