XSS in GitLab
CVE-2026-1090
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 10.6 before 18.7.6, 18.8 before 18.8.6, and 18.9 before 18.9.2 that could have allowed an authenticated user, when the `markdown_placeholders` feature flag was enabled, to inject JavaScript in a browser due to improper sanitization of placeholder content in markdown processing.
Vulnerability class: XSS (Cross-Site Scripting)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.7 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:N.
EPSS exploit prediction
EPSS: 0.002 (12.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 13th percentile — 12.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- GitLab — versions 10.6, 18.8, 18.9
Weakness classification (CWE)
References
- hackerone.com/reports/3502450 (Permissions Required, technical-description, permissions-required, exploit)
- gitlab.com/gitlab-org/gitlab/-/work_items/586478 (Broken Link)
- about.gitlab.com/releases/2026/03/11/patch-release-gitlab-18-9-2-released/ (Release Notes, Vendor Advisory)
Frequently asked questions
- What is CVE-2026-1090?
- CVE-2026-1090 is a high-severity vulnerability in GitLab, classified under Cross-site Scripting. CVSS score: 8.7/10. Published 2026-03-11.
- How severe is CVE-2026-1090?
- High severity. CVSS v3 base score is 8.7 out of 10.