I am creating a Javascript web-application front-finish that transmits user posted data to back-finish as GET-demands (JSONP). Back-finish and sanitation there's not the issue, however the URL-side...

I've found that after customers card inserts e.g. line-feeds in forms plus they get encoded to url-parameters, it doesn't work correctly even if url-encoded. E.g. http://app.domain.com/controller/action/param:userdata%0Amore_userdata...

CakePHP handles by using mod_rewrite and handles the parameters. Using the following kind of url, I recieve 404 Not found error. Basically take away the line feed (0A), it always works fine. I've also looked here that slashes / and may cause problems.

My question here is when I remove all line-feeds and slashes from user inputs, shall we be held safe and sound here right in front-finish? Or exist more chars which i should concern yourself with?