Appointment Scheduler 3.0 is vulnerable to CSV Injection via a Language > Labels > Export action.

A lack of rate limiting in pjActionAjaxSend in Appointment Scheduler 3.0 allows attackers to cause resource exhaustion.

Appointment Scheduler 3.0 is vulnerable to Multiple Stored Cross-Site Scripting (XSS) issues via the name, plugin_sms_api_key, plugin_sms_country_code, calendar_id, title, country name, or customer_name parameter.

Appointment Scheduler 3.0 is vulnerable to Multiple HTML Injection issues via the SMS API Key or Default Country Code.

User enumeration is found in in PHPJabbers Appointment Scheduler 3.0. This issue occurs during password recovery, where a difference in messages could allow an attacker to determine if the user is valid or not, enabling a brute force attack with valid users.

There is a Cross Site Scripting (XSS) vulnerability in the "theme" parameter of preview.php in PHPJabbers Appointment Scheduler v3.0