In FusionPBX up to v4.5.7, the file app\contacts\contact_urls.php uses an unsanitized "id" variable coming from the URL, which is reflected in HTML, leading to XSS.
https://resp3ctblog.wordpress.com/2019/10/19/fusionpbx-xss-12/
https://github.com/fusionpbx/fusionpbx/commit/a76d9637e31a70060ecc38786246a8b1c9178322