Security of launching Perl

I have a 3rd-party cgi script that's written in Perl and I have to use it. My entire site is in PHP3 (Linux / MySQL). I figure I can use system() or passthru() to launch a command like "/usr/bin/perl thescript.cgi" to achieve the required result. BUT ... is this secure? Forking off processes from a script launched from the web server? I know enough to know that I don't know enough about Linux security to be able to answer this question with absolute authority! Thanks, James.