Laravel 5.4.15 is vulnerable to Error based SQL injection in save.php via dhx_user and dhx_version parameters.
https://github.com/laravel/framework/blob/5.4/CHANGELOG-5.4.md
https://euvd.enisa.europa.eu/vulnerability/EUVD-2018-18091
http://www.itblog.gbonanno.de/cve-2018-6330-laravel-sql-injection/