CVE-2023-3500: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') in GitLab

Severity: medium (CVSS 6.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.5% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2023-08-02 · updated 2026-06-17
Weakness: CWE-79

Description

An issue has been discovered in GitLab CE/EE affecting all versions starting from 10.0 before 16.0.8, all versions starting from 16.1 before 16.1.3, all versions starting from 16.2 before 16.2.2. A reflected XSS was possible when creating specific PlantUML diagrams that allowed the attacker to perform arbitrary actions on behalf of victims.

Affected products

GitLab: from 10.0 before 16.0.8; from 16.1 before 16.1.3; from 16.2 before 16.2.2 — fixed in 16.0.8, 16.1.3, 16.2.2

How to fix

Upgrade to a fixed version: GitLab 16.0.8, 16.1.3, 16.2.2. Check the vendor advisory for mitigations.

References

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