CVE-2026-41658: Admidio's Missing Authorization on Inventory Module Destructive Endpoints Allows Any Authenticated User to Delete Items

The Admidio inventory module enforces authorization for destructive operations (delete, retire, reinstate) only in the UI layer by conditionally rendering buttons. The backend POST handlers at modules/inventory.php for item_delete, item_retire, item_reinstate, item_picture_upload, item_picture_save, and item_picture_delete perform CSRF validation but never check whether the requesting user is an inventory administrator. Any authenticated user who can access the inventory module can permanently delete any inventory item and all its associated data.