CVE-2026-18433 in GitLab
Summary
by MITRE • 08/12/2026
GitLab has remediated an issue in GitLab EE affecting all versions from 19.1 before 19.1.4 and 19.2 before 19.2.2 that under certain conditions could have allowed an authenticated user to read policy configuration belonging to a namespace they were not authorized to access, due to incorrect authorization checks in a GraphQL query.
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Analysis
by VulDB Data Team • 08/12/2026
This vulnerability represents a critical authorization bypass flaw in GitLab Enterprise Edition that undermines the fundamental security boundaries of namespace access controls. The issue stems from insufficient validation within GraphQL query processing mechanisms that govern how users interact with policy configurations across different namespaces. An authenticated user could exploit this weakness to retrieve sensitive policy information from namespaces where they lack proper authorization, effectively circumventing the intended access control matrix.
The technical root cause lies in improper authorization checks implemented within GitLab's GraphQL API endpoints responsible for fetching policy configuration data. When processing queries related to namespace policies, the system failed to adequately validate whether the requesting user possessed sufficient privileges to access the target namespace resources. This authorization gap allowed malicious actors with legitimate login credentials to craft specific GraphQL requests that would bypass standard permission enforcement mechanisms, enabling them to traverse namespace boundaries and obtain unauthorized access to policy configurations.
From an operational impact perspective, this vulnerability creates significant risk for organizations relying on GitLab's namespace-based security model. Policy configurations often contain sensitive information about access controls, compliance requirements, and organizational security practices that should remain confined to authorized personnel within specific project contexts. The ability to read unauthorized policy data could enable attackers to map out organizational structures, identify security gaps, and potentially escalate privileges through further exploitation of discovered information.
Security professionals should note this vulnerability aligns with CWE-285, which addresses improper authorization in software systems, and maps to ATT&CK technique T1078.004 for valid accounts and credential access. The flaw demonstrates how GraphQL implementations can introduce subtle authorization weaknesses when traditional access control mechanisms are not properly enforced at the query level. Organizations should immediately apply the patched versions 19.1.4 and 19.2.2 to remediate this issue, as the vulnerability could be exploited by both internal users with legitimate accounts and external attackers who have gained initial access to the GitLab instance.
Mitigation strategies beyond patching include implementing additional monitoring for unusual GraphQL query patterns that might indicate attempted privilege escalation, reviewing existing access control policies to ensure proper namespace isolation, and conducting thorough security audits of all API endpoints that handle sensitive configuration data. Organizations should also consider implementing rate limiting and anomaly detection mechanisms specifically designed to identify suspicious GraphQL request behaviors that could indicate exploitation attempts against similar authorization vulnerabilities.