In FusionPBX up to v4.5.7, the file resources\paging.php has a paging function (called by several pages of the interface), which uses an unsanitized "param" variable constructed partially from the URL args and reflected in HTML, leading to XSS.
https://resp3ctblog.wordpress.com/2019/10/19/fusionpbx-xss-15/
https://github.com/fusionpbx/fusionpbx/commit/23581e56e9a4d1685ddf1c7d67137417d654e134