The User Registration & Membership WordPress plugin before 4.1.3 does not properly validate data in an AJAX action when the Membership Addon is enabled, allowing attackers to authenticate as any user, including administrators, by simply using the target account's user ID.
The User Registration & Membership WordPress plugin before 4.1.2 does not prevent users to set their account role when the Membership Addon is enabled, leading to a privilege escalation issue and allowing unauthenticated users to gain admin privileges