@strapi/plugin-content-manager leaks data via relations via the Admin Panel

Summary

1. If a super admin creates a collection where an item in the collection has an association to another collection, a user with the Author Role can see the list of associated items they did not create. They should only see their own items that they created, not all items ever created.

Details

At the top level every collection shows blank items for an Author if they did not create the item. This is ideal and works great. However if you associate one private collection to another private collection and an Author creates a new item. The pull down should not show the admins list of previously created items. It should be blank unitl they add their own items.

PoC

1. Sign in as Admin. Navigate to content creation.
2. Select a collection and verify you have items you created there. And that they have associations to other protected collections.
3. Verify role permissions for your collections are set to CRUD if user created.
4. Log out and sign in as a unrelated Author.
5. Navigate to content management and verify you see collections built by admin but empty for you (as expected)
6. Create a new item as an Author and see the card appear with attributes to fill out.
7. Use the form pull down for the associations.
8. Notice that protected collection items from Admin appear in drop down. These should be hidden

Impact

Security vulnerability where authors have access to protected data created by admin. This could be passwords emails or any other item created for the admin's collection.

See images below for more context

Permissions set

Good at top level no items seen

Drop down in Author login can see Admin data