CVE-2026-1388

Received Received - Intake

ReDoS Vulnerability in GitLab Merge Request Endpoint

Publication date: 2026-02-25

Last updated on: 2026-02-28

Assigner: GitLab Inc.

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.

CVSS Scores

EPSS Scores

Probability:
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Meta Information

Published

2026-02-25

Last Modified

2026-02-28

Generated

2026-07-06

AI Q&A

2026-02-25

EPSS Evaluated

2026-07-05

NVD

CVE-2026-1388

EUVD

EUVD-2026-8721

Affected Vendors & Products

Vendor	Product	Version / Range
gitlab	gitlab	From 18.8.0 (inc) to 18.8.5 (exc)
gitlab	gitlab	From 18.8.0 (inc) to 18.8.5 (exc)
gitlab	gitlab	18.9.0
gitlab	gitlab	18.9.0
gitlab	gitlab	From 9.2.0 (inc) to 18.7.5 (exc)
gitlab	gitlab	From 9.2.0 (inc) to 18.7.5 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-1333	The product uses a regular expression with an inefficient, possibly exponential worst-case computational complexity that consumes excessive CPU cycles.

Attack-Flow Graph

Executive Summary

This vulnerability in GitLab CE/EE affects versions from 9.2 before 18.7.5, 18.8 before 18.8.5, and 18.9 before 18.9.1. It allows an unauthenticated user to cause a regular expression denial of service (ReDoS) by sending specially crafted input to a merge request endpoint under certain conditions.

Impact Analysis

The impact of this vulnerability is a denial of service (DoS) condition. An attacker can cause the GitLab service to become unavailable or unresponsive by exploiting the regular expression processing in the merge request endpoint, potentially disrupting normal operations.

Compliance Impact

I don't know

Detection Guidance

I don't know

Mitigation Strategies

To mitigate this vulnerability, you should upgrade GitLab CE/EE to a fixed version. Specifically, update to version 18.7.5 or later if you are using the 18.7 series, 18.8.5 or later for the 18.8 series, or 18.9.1 or later for the 18.9 series.

This vulnerability allows an unauthenticated user to cause a denial of service via specially crafted input to a merge request endpoint, so applying the patch by upgrading is the recommended immediate action.

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