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.

Affected

GitLab

CVSS v3.1 GITLAB

7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

0.37% chance of exploitation in the next 30 days, 30th percentile

Published

2026-02-25

Updated

2026-02-26

Proof-of-concept exploits (1)

• https://hackerone.com/reports/3482893

Security advisories

• https://about.gitlab.com/releases/2026/02/25/patch-release-gitlab-18-9-1-released

References

• CVE Record
• NVD entry