Element Pack Addons for Elementor < 8.3.16 - Unauthenticated Email Header Injection via element_pack_contact_form

Description

The plugin is vulnerable to Email Header Injection via the `element_pack_contact_form` AJAX action. This is due to insufficient sanitization of newline characters in user-supplied input that gets concatenated into email headers. This makes it possible for unauthenticated attackers to inject arbitrary email headers into emails sent by the contact form.