GitLab, a leading DevOps platform, recently patched a critical Denial of Service (DoS) vulnerability discovered in October 2025. This security flaw, tracked as CVE-2025-10004, exposes GitLab instances to unauthenticated attackers capable of overwhelming systems by exploiting a weakness in the GraphQL API. Given GitLab’s pivotal role in continuous integration and development workflows, understanding this vulnerability and promptly applying patches is essential for administrators and security professionals.
What is the Vulnerability?
The flaw resides in the GraphQL API within GitLab Community and Enterprise Editions before versions 18.4.2, 18.3.4, and 18.2.8. Attackers can send specially crafted GraphQL queries requesting large repository blobs, which can exhaust server resources and cause operational disruption or unavailability. Importantly, this exploit does not require authentication, making public-facing GitLab instances particularly vulnerable.
Potential Impact
By exploiting this vulnerability, threat actors can:
- Cause severe performance degradation or full downtime of GitLab services.
- Disrupt development pipelines dependent on GitLab for source control and CI/CD.
- Potentially create openings for further exploitation during downtime or degraded service.
The vulnerability received a high severity rating, with a CVSS v3.1 base score of 7.5, highlighting its importance in security risk prioritization.
What Has GitLab Done?
GitLab responded swiftly by releasing patches in the recently published versions 18.4.2, 18.3.4, and 18.2.8. Additionally, GitLab.com and GitLab Dedicated customers were unaffected as these platforms are either patched or isolated from this exposure.
Moreover, GitLab disclosed other high-severity vulnerabilities patched simultaneously, including issues impacting GraphQL authorization and JSON file uploads that could also lead to DoS conditions.
How to Protect Your GitLab Instances
- Immediate Upgrade: Upgrade any self-managed GitLab instances to at least version 18.4.2, 18.3.4, or 18.2.8. Doing so ensures mitigation against this and other patched vulnerabilities.
- Monitor Official Advisories: Regularly review GitLab’s security advisories to stay informed of new risks or updates.
- Restrict Exposure: Where possible, limit public access to GitLab’s API endpoints or place them behind firewalls or gateway controls.
- Incident Preparedness: Have contingency plans to respond to DoS incidents that could impact service availability.
Conclusion
This latest DoS vulnerability in GitLab underscores the risks posed by unauthenticated API abuse and the importance of timely patch management. Security teams should prioritize upgrading affected systems and strengthen controls around GitLab exposure. Staying proactive in vulnerability monitoring and rapid remediation remains key to protecting critical development infrastructure.
For detailed patch notes and technical guidance, refer to GitLab’s official release page and security advisories.
