The Amelia WordPress plugin is vulnerable to Cross-Site Scripting due to insufficient escaping and sanitization of the lastName parameter found in the ~/src/Application/Controller/User/Customer/AddCustomerController.php file which allows attackers to inject arbitrary web scripts onto a pages that executes whenever a user accesses the booking calendar with the date the attacker has injected the malicious payload into. This affects versions up to and including 1.0.46.