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.
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Meta Information
Published
2026-02-25
Last Modified
2026-02-28
Generated
2026-06-16
AI Q&A
2026-02-25
EPSS Evaluated
2026-06-15
NVD
CVE-2026-1388
EUVD
EUVD-2026-8721
Affected Vendors & Products
Showing 6 associated CPEs
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
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KEV
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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.
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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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