The Bookly WordPress plugin before 28.3 does not properly verify a customer's identity before updating their stored details, allowing unauthenticated attackers who know a customer's primary identifier to overwrite that customer's stored personal information such as name, email and address.
https://wpscan.com/vulnerability/5bfed7cf-5bf3-4a3b-a2b6-9f9d48f52fd5/