# CVE-2026-3254: Improper Restriction of Rendered UI Layers or Frames in GitLab

> CVE-2026-3254: Improper Restriction of Rendered UI Layers or Frames in GitLab. CVSS 3.5 (CVSS 3.1).

Canonical: https://rewindex.com/cve/CVE-2026-3254
Last updated: 2026-06-17T10:43:16Z

- Published: 2026-04-22 16:29 UTC · Updated: 2026-06-17 10:43 UTC · Assigner: GitLab
- CVSS: 3.5 (CVSS 3.1) · Severity: Low · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
- EPSS: 0.15%, 4th percentile (scored 2026-10-25)
- CISA KEV: no
- CWE: CWE-1021

## 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 vendors and products

- GitLab: GitLab

## Tracked companies

- [GitLab](https://rewindex.com/company/gitlab.md)

## References

- [CVE record on cve.org](https://www.cve.org/CVERecord?id=CVE-2026-3254)
- [NVD entry](https://nvd.nist.gov/vuln/detail/CVE-2026-3254)
- [https://gitlab.com/gitlab-org/gitlab/-/work\_items/591587](https://gitlab.com/gitlab-org/gitlab/-/work_items/591587)
- [https://hackerone.com/reports/3572752](https://hackerone.com/reports/3572752)

---

_Sources: CVE records from the CVE Program (cve.org). CVE® is a registered trademark of The MITRE Corporation. (https://www.cve.org/) This product uses data from the NVD API but is not endorsed or certified by the NVD. (https://nvd.nist.gov/) Known Exploited Vulnerabilities catalog from CISA. (https://www.cisa.gov/known-exploited-vulnerabilities-catalog) EPSS scores from FIRST (Exploit Prediction Scoring System). (https://www.first.org/epss/)_


---
Canonical: https://rewindex.com/cve/CVE-2026-3254 · Markdown: https://rewindex.com/cve/CVE-2026-3254.md · JSON: https://rewindex.com/api/v1/cves/CVE-2026-3254 · Data licensed CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) · Generated 2026-10-26T03:09:41.782Z