The User Registration & Membership plugin for WordPress is vulnerable to authentication bypass in versions up to, and including, 5.1.2. This is due to incorrect authentication in the 'register_member' function. This makes it possible for unauthenticated attackers to log in a newly registered user on the site who has the 'urm_user_just_created' user meta set.
The User Registration & Membership – Custom Registration Form, Login Form, and User Profile plugin for WordPress is vulnerable to Insecure Direct Object Reference in all versions up to, and including, 5.1.2 via the 'register_member' function, due to missing validation on the 'member_id' user controlled key. This makes it possible for unauthenticated attackers to delete arbitrary user accounts that newly registered on the site who has the 'urm_user_just_created' user meta set.