Regular Expression Denial of Service in GitLab Community and Enterprise Edition
CVE-2026-1388

7.5HIGH

Key Information:

Vendor

Gitlab
Status
Gitlab
Vendor
CVE Published:
25 February 2026

What is CVE-2026-1388?

A vulnerability in GitLab CE/EE allows an unauthenticated user to perform a regular expression denial of service attack. By sending specially crafted inputs to a specific merge request endpoint under certain conditions, this vulnerability could disrupt the service, rendering it inoperable. Remediation has been implemented in versions 18.7.5, 18.8.5, and 18.9.1, following the discovery of the issue. Detailed technical insights can be referenced in the associated GitLab issue and HackerOne report.

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Deploy the Patch

Affected Version(s)

GitLab 9.2 < 18.7.5

GitLab 18.8 < 18.8.5

GitLab 18.9 < 18.9.1

References

https://gitlab.com/gitlab-org/gitlab/-/issues/587560
issue-trackingpermissions-required
https://hackerone.com/reports/3482893
technical-descriptionexploitpermissions-required
https://about.gitlab.com/releases/2026/02/25/patch-releas...

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

Credit

Thanks [sim4n6](https://hackerone.com/sim4n6) for reporting this vulnerability through our HackerOne bug bounty program
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