CVE-2026-1388

HIGH

GitLab 9.2-18.7.4, 18.8-18.8.4, 18.9.0 - ReDoS via Merge Request Endpoint

Title source: llm

Description

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.

References (3)

Core 3

Core References

Release Notes

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

Issue Tracking issue-tracking permissions-required

https://gitlab.com/gitlab-org/gitlab/-/issues/587560

Third Party Advisory technical-description exploit permissions-required

https://hackerone.com/reports/3482893

Scores

CVSS v3 7.5

EPSS 0.0036

EPSS Percentile 27.3%

Attack Vector NETWORK

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

CISA SSVC

Vulnrichment

Exploitation poc

Automatable yes

Technical Impact partial

Details

CWE

CWE-1333

Status published

Products (2)

gitlab/gitlab 18.9.0 (2 CPE variants)

gitlab/gitlab 9.2.0 - 18.7.5 (2 CPE variants)

Published Feb 25, 2026

Tracked Since Feb 26, 2026