Keyy Two Factor Authentication (like Clef) <= 1.2.3 - Authenticated (Subscriber+) Privilege Escalation via Account Takeover

The Keyy Two Factor Authentication (like Clef) plugin for WordPress is vulnerable to privilege escalation via account takeover in all versions up to, and including, 1.2.3. This is due to the plugin not properly validating a user's identity associated with a token generated. This makes it possible for authenticated attackers, with subscriber-level access and above, to generate valid auth tokens and leverage that to auto-login as other accounts, including administrators, as long as the administrator has the 2FA set up.