EUVD-2025-209367
GHSA-m3c6-4xg4-583x
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N
Lifecycle Timeline
3Description
GitLab has remediated an issue in GitLab EE affecting all versions from 16.6 before 18.8.9, 18.9 before 18.9.5, and 18.10 before 18.10.3 that under certain circumstances could have allowed an authenticated user to have access to other users' email addresses via certain GraphQL queries.
Analysis
Authenticated users in GitLab EE versions 16.6-18.8.8, 18.9-18.9.4, and 18.10-18.10.2 can expose other users' email addresses through specific GraphQL queries due to improper authorization checks. An authenticated attacker can enumerate valid user accounts and retrieve their email addresses without additional privileges, violating confidentiality. No public exploit code or active exploitation has been confirmed; patches are available in GitLab 18.8.9, 18.9.5, and 18.10.3.
Technical Context
The vulnerability stems from insufficient authorization validation (CWE-862: Missing Authorization) in GitLab's GraphQL API endpoint. GitLab EE implements role-based access control for user data exposure, but certain GraphQL query constructs bypass these checks, allowing an authenticated user to traverse the schema and retrieve email attributes meant to be restricted. The root cause is a logic flaw in GraphQL field resolver authorization rather than a cryptographic or injection vulnerability. This affects only GitLab EE (Enterprise Edition); Community Edition is unaffected per vendor statement.
Affected Products
GitLab EE (Enterprise Edition) versions 16.6 through 18.8.8, 18.9.0 through 18.9.4, and 18.10.0 through 18.10.2 are affected. Community Edition and other GitLab editions are not vulnerable. Patch availability confirmed for GitLab 18.8.9, 18.9.5, and 18.10.3 per vendor release notes (https://about.gitlab.com/releases/2026/04/08/patch-release-gitlab-18-10-3-released/). See also GitLab issue https://gitlab.com/gitlab-org/gitlab/-/issues/565363 and HackerOne report https://hackerone.com/reports/3303810 for additional context.
Remediation
Upgrade GitLab EE to patched versions: 18.8.9 or later, 18.9.5 or later, or 18.10.3 or later, depending on your current deployment track. If immediate patching is not feasible, restrict GraphQL API access via firewall or reverse-proxy rules to limit authenticated query execution, or disable public GraphQL query introspection. Audit GraphQL query logs for anomalous user-enumeration patterns and review user access to sensitive data endpoints. Refer to the official GitLab security advisory (https://about.gitlab.com/releases/2026/04/08/patch-release-gitlab-18-10-3-released/) and the issue tracker (https://gitlab.com/gitlab-org/gitlab/-/issues/565363) for full remediation guidance.
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External POC / Exploit Code
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