In FusionPBX up to v4.5.7, the file app\basic_operator_panel\resources\content.php uses an unsanitized "eavesdrop_dest" variable coming from the URL, which is reflected on 3 occasions in HTML, leading to XSS.
https://resp3ctblog.wordpress.com/2019/10/19/fusionpbx-xss-18/
https://github.com/fusionpbx/fusionpbx/commit/7fec1014ff0d08e36be6a3f7664edb3a9df7b4ac