OTP-less one tap Sign in 2.0.14 - 2.0.59 - Unauthenticated Arbitrary Email Update to Account Takeover/Privilege Escalation

The OTP-less one tap Sign in plugin for WordPress is vulnerable to privilege escalation via account takeover in versions 2.0.14 to 2.0.59. This is due to the plugin not properly validating a user's identity prior to updating their details, like email. This makes it possible for unauthenticated attackers to change arbitrary users' email addresses, including administrators, and leverage that to reset the user's password and gain access to their account.
Additionally, the plugin returns authentication cookies in the response, which can be used to access the account directly.