The Relais 2FA plugin for WordPress is vulnerable to authentication bypass in versions up to, and including, 1.0. This is due to incorrect authentication and capability checking in the rl_do_ajax function. This makes it possible for unauthenticated attackers to log in as any existing user on the site, such as an administrator, if they have access to the email.
A product requires authentication, but the product has an alternate path or channel that does not require authentication.