CVE-2020-10085 in Community Edition
Summary
by MITRE
GitLab 12.3.5 through 12.8.1 allows Information Disclosure. A particular view was exposing merge private merge request titles.
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Analysis
by VulDB Data Team • 03/14/2020
This vulnerability exists within GitLab's access control mechanisms affecting versions 12.3.5 through 12.8.1 where a specific view was inadvertently exposing private merge request titles to unauthorized users. The flaw represents a critical information disclosure issue that violates fundamental security principles of data confidentiality and access control. According to CWE-200, this vulnerability falls under information exposure, specifically where sensitive data is accessible beyond intended authorization boundaries. The technical implementation appears to have failed to properly enforce access controls on merge request views, allowing users without appropriate permissions to access private merge request titles through a particular interface or endpoint.
The operational impact of this vulnerability extends beyond simple information leakage as it compromises the integrity of GitLab's collaborative workflow and project management capabilities. Private merge requests often contain sensitive information about upcoming features, security patches, or strategic changes that should remain confidential until deployment. Attackers could exploit this vulnerability to gain intelligence about project development timelines, feature implementations, and potentially identify security vulnerabilities in advance of their public disclosure. This information disclosure aligns with ATT&CK technique T1211 which involves privilege escalation through information gathering, and T1566 which covers social engineering via information gathering.
The vulnerability demonstrates a failure in the principle of least privilege and proper authorization checking within GitLab's codebase. When users access merge request views, the system should validate whether they have appropriate permissions to view the specific merge request, including checking project membership, access levels, and permission scopes. The exposure of private merge request titles indicates that the authorization logic either failed to check user permissions correctly or bypassed normal access control checks for this particular view. Organizations using affected GitLab versions face significant risk as this vulnerability could enable adversaries to map project structures, identify development activities, and potentially plan targeted attacks against specific development workflows.
Mitigation strategies should prioritize immediate patching to versions 12.8.2 or later where the vulnerability has been addressed through proper access control enforcement. Organizations should also implement network-level monitoring to detect unusual access patterns to merge request views and consider temporary restrictions on merge request visibility for sensitive projects. The fix likely involved strengthening authorization checks in the merge request view rendering logic to ensure that private merge request titles are only accessible to users with appropriate project permissions, typically aligning with CWE-668 which addresses insufficient protection of resource identifiers. Security teams should conduct comprehensive audits of access controls across all GitLab features and implement regular security testing to prevent similar information disclosure vulnerabilities in the future.