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.
Exploitability
AV:NAC:HPR:NUI:NScope
S:UImpact
C:HI:HA:H8.1/CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:HOther