CVE-2026-5309 in Enterprise Edition
Summary
by MITRE • 06/25/2026
GitLab has remediated an issue in GitLab EE affecting all versions from 18.6 before 18.11.6, 19.0 before 19.0.3, and 19.1 before 19.1.1 that under certain conditions could have allowed an authenticated user to read or modify another group's virtual registry cleanup policy settings without authorization.
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Analysis
by VulDB Data Team • 06/25/2026
This vulnerability represents a critical access control flaw in GitLab Enterprise Edition that undermines the integrity of group-level registry management configurations. The issue stems from insufficient authorization checks within the virtual registry cleanup policy functionality, allowing authenticated users to bypass normal permission boundaries and manipulate settings belonging to other groups. Such a weakness directly violates fundamental security principles of least privilege and separation of duties that are essential for maintaining secure multi-tenant environments.
The technical implementation flaw manifests in the validation logic governing registry cleanup policy operations where the system fails to properly verify whether an authenticated user possesses adequate permissions to access or modify specific group resources. This authorization bypass occurs under specific conditions that likely involve particular user roles or registry configurations, making the vulnerability both targeted and potentially exploitable by users with lower privilege levels who should not have access to cross-group administrative functions. The vulnerability aligns with CWE-285 which addresses improper authorization in software systems, representing a clear violation of access control mechanisms.
From an operational impact perspective, this vulnerability exposes organizations to significant risks including unauthorized modification of critical registry cleanup policies that could lead to data retention issues, compromised storage management, or potential exposure of sensitive artifacts. Attackers could potentially disrupt automated cleanup processes, manipulate retention periods for registry images, or gain insights into other groups' infrastructure configurations through policy examination. The implications extend beyond simple configuration changes as registry cleanup policies often contain critical operational metadata and security-related settings that govern how container images are managed and retained within the system.
The remediation efforts in GitLab addresses this issue through enhanced authorization checks that properly validate user permissions against group boundaries before allowing access to virtual registry cleanup policy operations. This fix aligns with ATT&CK technique T1078 which covers valid accounts and privilege escalation, as the vulnerability allowed unauthorized access through legitimate authenticated sessions. Organizations should immediately apply the patched versions to prevent potential exploitation while implementing additional monitoring for unusual registry policy modification activities that might indicate attempted exploitation of this vulnerability.
Security teams should consider this vulnerability as part of broader registry security assessments and implement comprehensive audit logging for all registry cleanup policy operations across all groups within their GitLab environments. The remediation process demonstrates GitLab's commitment to addressing authorization-related issues that could compromise multi-tenant security models, particularly in enterprise deployments where strict segregation of group resources is essential for maintaining organizational security boundaries.