CVE-2023-5226: Improper Control of Generation of Code ('Code Injection') in GitLab

Severity: high (CVSS 7.5 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: 2023-12-01 · updated 2026-06-17
Weakness: CWE-94

Description

An issue has been discovered in GitLab affecting all versions before 16.4.3, all versions starting from 16.5 before 16.5.3, all versions starting from 16.6 before 16.6.1. Under certain circumstances, a malicious actor bypass prohibited branch checks using a specially crafted branch name to manipulate repository content in the UI.

Affected products

GitLab: before 16.4.3; from 16.5.0 before 16.5.3; 16.6.0 — fixed in 16.4.3, 16.5.3

How to fix

Upgrade to a fixed version: GitLab 16.4.3, 16.5.3. Check the vendor advisory for mitigations.

References

https://gitlab.com/gitlab-org/gitlab/-/issues/426400
https://hackerone.com/reports/2173053
https://gitlab.com/gitlab-org/gitlab/-/issues/426400
https://hackerone.com/reports/2173053

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