GitLab CE/EE <18.8.7/18.9.3/18.10.1: Auth Hijack XSS via Mermaid Diagrams
CVE-2026-2973 Published on March 25, 2026
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in GitLab
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.
Vulnerability Analysis
CVE-2026-2973 can be exploited with network access, requires user interaction and a small amount of user privileges. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have a small impact on confidentiality and integrity, and no impact on availability.
Weakness Type
What is a XSS Vulnerability?
The software does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.
CVE-2026-2973 has been classified to as a XSS vulnerability or weakness.
Products Associated with CVE-2026-2973
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Affected Versions
GitLab:- Version 17.7 and below 18.8.7 is affected.
- Version 18.9 and below 18.9.3 is affected.
- Version 18.10 and below 18.10.1 is affected.
Exploit Probability
EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.