CVE-2025-3396 in Enterprise Edition
Summary
by MITRE • 07/10/2025
An issue has been discovered in GitLab EE affecting all versions from 13.3 before 17.11.6, 18.0 before 18.0.4, and 18.1 before 18.1.2 that could have allowed authenticated project owners to bypass group-level forking restrictions by manipulating API requests.
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Analysis
by VulDB Data Team • 07/25/2025
This vulnerability in GitLab Enterprise Edition represents a critical access control flaw that undermines the security model designed to protect group-level forking restrictions. The issue affects a broad range of versions including 13.3 through 17.10.5, 18.0 through 18.0.3, and 18.1 through 18.1.1, indicating a long-standing problem that has persisted across multiple release cycles. The vulnerability specifically targets the authorization mechanisms that govern how project owners interact with group-level forking policies, creating a pathway for malicious actors to circumvent intended security controls. This represents a direct violation of the principle of least privilege and could enable unauthorized access to protected resources within GitLab's collaborative development environment.
The technical flaw manifests through API request manipulation that allows authenticated project owners to bypass group-level forking restrictions that should normally prevent projects from being forked outside their designated groups. This vulnerability stems from insufficient validation of group membership and forking permissions during API interactions, enabling attackers to craft requests that appear legitimate but effectively circumvent the security controls. The exploitation requires authentication as a project owner, but once achieved, allows the attacker to perform forking operations that should be restricted at the group level. This issue aligns with CWE-284 which describes improper access control vulnerabilities, specifically focusing on insufficient authorization checks that permit unauthorized operations.
The operational impact of this vulnerability extends beyond simple privilege escalation, potentially enabling attackers to access sensitive code repositories, manipulate development workflows, and compromise the integrity of group-level security policies. Project owners who should only be able to fork projects within their designated groups could inadvertently or maliciously create forks in unauthorized locations, potentially exposing confidential code or violating organizational security policies. This vulnerability could be particularly dangerous in enterprise environments where strict access controls are maintained to prevent code leakage or unauthorized collaboration with external parties. The impact is amplified by the fact that the vulnerability affects multiple major release versions, suggesting widespread exposure across organizations that may not have immediately patched their systems.
Organizations should immediately implement mitigations including applying the latest security patches to all affected GitLab versions, conducting comprehensive access control audits, and monitoring API usage patterns for suspicious forking activities. System administrators should also review and validate existing group-level forking policies to ensure proper enforcement, while security teams should implement additional monitoring controls around API endpoints related to forking operations. The vulnerability demonstrates the critical importance of maintaining up-to-date security patches and the need for continuous security validation in collaborative development platforms. This issue also highlights the necessity of implementing defense-in-depth strategies that include multiple layers of access control validation beyond basic authentication. Organizations should consider implementing automated tools to detect and prevent unauthorized forking operations while maintaining detailed audit logs of all forking activities for forensic analysis purposes. The vulnerability serves as a reminder that even well-established security controls can be bypassed through subtle implementation flaws in API authorization mechanisms, requiring constant vigilance and proactive security measures.