Executive brief
django CMS is a content management system that allows editors to manage page structure and content. A flaw in the frontend-editing structure endpoint failed to properly authorize access to non-PageContent objects, allowing any authenticated staff user to view the internal placeholder and plugin structure of objects they are not permitted to edit. This discloses editorial metadata about private objects owned by other staff members, including placeholder names, plugin hierarchy, and object existence—though not actual field data or write access.
Technical details
The `render_object_structure` view in django CMS processes requests to the endpoint `GET /<lang>/admin/cms/placeholder/object/<content_type_id>/structure/<object_id>/` to expose CMS structure metadata for frontend editing. For non-PageContent objects (those using PlaceholderRelationField), the view did not perform object-level authorization checks before returning the structure. An authenticated staff user could enumerate or guess the content_type_id and object_id to retrieve placeholder/plugin trees of any object in the system, bypassing both model-level change permissions and the `cms.use_structure` permission. PageContent objects were already protected via a separate check. The vulnerability is read-only, disclosing structure metadata (placeholder slot names, plugin tree, plugin identifiers) rather than field data or edit access. Fix available in version 5.0.9 and later, which applies object-level authorization mirroring `Placeholder.has_change_permission`, returning HTTP 404 when unauthorized.
Affected products
- Django CMS Project django-cms 4.0.0 through 5.0.x, and 5.1.0a1
Timeline
- 2026-08-20: disclosed: Advisory published to GitHub Advisory Database
- 2026: patched: Fixed in version 5.0.9