GHSA-8QJ2-C6Q4-F399 django CMS: Missing authorization in `render_object_structure` discloses non-PageContent placeholder structure to low-privileged staff

Summary The django-cms frontend-editing structure endpoint GET //admin/cms/placeholder/object//structure// did not perform an object-level authorization check for non-PageContent objects. Any authenticated, active staff user could request the structure endpoint for a frontend-editable object a...