CVE-2026-8839: Authorization Bypass Through User-Controlled Key

The MapPress Maps for WordPress plugin for WordPress is vulnerable to Authorization Bypass Through User-Controlled Key in all versions up to, and including, 2.96.6. This is due to missing ownership verification in the REST API routes registered via `Mappress_Api::rest_api_init()`, where the GET `/wp-json/mapp/v1/maps/{mapid}` endpoint uses `'permission_callback' => '__return_true'` and the write endpoints (POST update, DELETE, PATCH mutate, POST clone, POST empty_trash) only check the generic `edit_posts` capability without confirming that the requester owns the targeted map — a gap that is not compensated at the model layer, as `Mappress_Map::get()`, `save()`, `delete()`, `mutate()`, and `empty_trash()` all operate on any caller-supplied map ID without an ownership check. This makes it possible for unauthenticated attackers to read sensitive map data — including POI titles, addresses, coordinates, and body content — for any map on the site by enumerating map IDs, and for authenticated attackers with Contributor-level access and above to modify, delete, trash/restore, or clone any map regardless of its author.