CVE-2026-3254

LOW

Improper Restriction of Rendered UI Layers or Frames in GitLab

Title source: cna

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.

References (2)

[Exploit] https://hackerone.com/reports/3572752

https://gitlab.com/gitlab-org/gitlab/-/work_items/591587

Scores

CVSS v3 3.5

Attack Vector NETWORK

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N

Details

CWE

CWE-1021

Status published

Products (1)

GitLab/GitLab 18.11 - 18.11.1

Published Apr 22, 2026

Tracked Since Apr 22, 2026