CVE-2026-1388: Inefficient Regular Expression Complexity in GitLab
GitLab has remediated an issue in GitLab CE/EE affecting all versions from 9.2 before 18.7.5, 18.8 before 18.8.5, and 18.9 before 18.9.1 that could have allowed an unauthenticated user to cause regular expression denial of service by sending specially crafted input to a merge request endpoint under certain conditions.
Other sources
GitLab has remediated an issue that could have allowed an unauthenticated user to cause regular expression denial of service by sending specially crafted input to a merge request endpoint under certain conditions.
— GitLab
Affected Software
Remediation
Information
Event History
Peer vulnerabilities
Found alongside the following vulnerabilities.
Frequently Asked Questions
What is the severity of CVE-2026-1388?
CVE-2026-1388 has a high severity rating as it allows unauthenticated users to exploit a regular expression denial of service vulnerability in GitLab.
How do I fix CVE-2026-1388?
To remediate CVE-2026-1388, you should upgrade your GitLab installation to version 18.7.5, 18.8.5, or 18.9.1.
Which versions are affected by CVE-2026-1388?
CVE-2026-1388 affects all GitLab versions from 9.2 up to but not including 18.7.5, 18.8 up to 18.8.5, and 18.9 up to 18.9.1.
What type of vulnerability is CVE-2026-1388?
CVE-2026-1388 is categorized as a Regular Expression Denial of Service (ReDoS) vulnerability.
Is CVE-2026-1388 present in both GitLab CE and EE versions?
Yes, CVE-2026-1388 affects both GitLab Community Edition (CE) and Enterprise Edition (EE) versions.