Dangerous PHP Functions Enabled

We recommend disabling the following functions on your server, or at least in the directory that your community is installed in. If you do not manage your server yourself, your hosting provider will be able to assist with this.
exec, system, pcntl_exec, popen, proc_open, shell_exec

It means that those functions are enabled in the server side PHP settings. On a WHM/CPanel server, log in to CPanel and edit the php.ini file found there. It should have a section labeled disable_functions =

Place a quote symbol followed by those functions and an end quote. Save and reboot Apache (or w/e we server you have).