Medium [CVE-2026-80183] Information disclosure via improper handling of domain IDs in role assignment listings

In OpenStack Keystone before 29.0.3, any authenticated user holding role:reader on any project can list every project-scoped role assignment under any domain by passing a domain ID as scope.project.id with include_subtree to the GET /v3/role_assignments endpoint.

The domain's project record has domain_id=null, causing the policy domain_id check to pass for any caller. With include_names, the response discloses the names and home-domain IDs of every user, group, project, and role involved.

The literal "default" domain ID works against any deployment created with keystone-manage bootstrap. An attacker can harvest domain IDs from the response and repeat the query to map role assignments across the entire cloud.

This is caused by misuse of "None" in list_role_assignments_for_tree. This leads to the disclosure of names and home-domain IDs for users, groups, projects, and roles throughout the cloud infrastructure.

This vulnerability was introduced in OpenStack Train 16.0.0 and affects all Red Hat OpenStack Platform versions shipping Keystone versions before the fixes (27.1.0, 28.1.0, 29.1.0). Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N).

Weakness: CWE-639. Affected Red Hat products: Red Hat OpenStack Platform 13 (Queens); Red Hat OpenStack Platform 16.2; Red Hat OpenStack Platform 17.1; Red Hat OpenStack Platform 18.0.