The Frontend Login and Registration Blocks plugin for WordPress is vulnerable to privilege escalation via account takeover in all versions up to, and including, 1.0.7. This is due to the plugin not properly validating a user's identity prior to updating a password. This makes it possible for authenticated attackers, with Subscriber-level access and above, to change arbitrary user's passwords, including administrators, and leverage that to gain access to their account.
When setting a new password for a user, the product does not require knowledge of the original password, or using another form of authentication.