Not CF specific per se, but I would also make sure you are looking into CORS
https://developer.mozilla.org/en-US/docs/Web/HTTP/CORS and that you are setting access control headers to prevent unauthorized scripts from running on your application if something does get past your security and starts adding some skimming script to your code to capture data and send it to a 3rd party. I have dealt with several issues for clients over the last couple years where setting those helped.