What’s Vulnerable › Vulnerabilities

CVE-2026-2973: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in GitLab

• Severity: medium (CVSS 5.4 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-03-25 · updated 2026-06-17
• Weakness: CWE-79

Description

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 17.7 before 18.8.7, 18.9 before 18.9.3, and 18.10 before 18.10.1 that could have allowed an authenticated user to execute arbitrary JavaScript in a user's browser due to improper sanitization of entity-encoded content in Mermaid diagrams.

Affected products

• GitLab: from 17.7.0 before 18.8.7; from 18.9.0 before 18.9.3; 18.10.0 — fixed in 18.8.7, 18.9.3

How to fix

Upgrade to a fixed version: GitLab 18.8.7, 18.9.3. Check the vendor advisory for mitigations.

References

• https://about.gitlab.com/releases/2026/03/25/patch-release-gitlab-18-10-1-released/
• https://gitlab.com/gitlab-org/gitlab/-/work_items/591049
• https://hackerone.com/reports/3566802

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