Open Object provides an API and admin interface to manage objects and object types. From 2.4.3 until 2.5.1, 3.6.2, 4.0.2, and 4.1.1, a token scoped to read one ObjectType can read the full versioned record of an object of any other ObjectType via the history-detail endpoint GET /api/v2/objects/{uuid}/{index}. The history_detail action in src/objects/api/v2/views.py calls self.get_queryset() and get_object_or_404 directly instead of self.get_object(), so check_object_permissions and the per-object check in ObjectTypeBasedPermission.has_object_permission are not invoked. The queryset's filter_for_token applies only to the list and search actions, while ObjectTypeBasedPermission.has_permission allows non-create actions, leaving neither check to constrain history-detail records to the token's…