PHP: Security when using CURL?

Question

I have a page like this. User write an URL into a form and submit. Once the URL is submitted, I connect that page with CURL, search for a string. If it finds the string, it adds

Answer 1

curl makes a request and to a server and the server sends back data. If there were an executable file on a web server you'd get back the binary of the file. Unless you write the file to your disk and execute it there should be no problem. Security in that sense should not be an issue.