The Church Admin plugin for WordPress is vulnerable to Server-Side Request Forgery in all versions up to, and including, 5.0.28 due to insufficient validation of user-supplied URLs in the 'audio_url' parameter. This makes it possible for authenticated attackers, with Administrator-level access, to make web requests to arbitrary locations originating from the web application and can be used to query and modify information from internal services.
https://plugins.trac.wordpress.org/browser/church-admin/trunk/includes/sermon-podcast.php#L1181
https://plugins.trac.wordpress.org/browser/church-admin/trunk/includes/functions.php#L6297
https://plugins.trac.wordpress.org/browser/church-admin/tags/5.0.27/includes/functions.php#L6297