The MagicForm WordPress plugin through 0.1.3 does not properly validate the type of files uploaded through an unauthenticated AJAX action when a form's per-field extension allowlist is left empty, allowing unauthenticated attackers to upload PHP files and execute arbitrary code on the server.
https://wpscan.com/vulnerability/043f449f-fc65-4218-83d2-7742e62f2af3/