Hey, and welcome to the forums!!!!
Yes it is bad for you and worse if you have CF.
You already have a form of lung disease because of CF. Your lungs get bashed everyday by infection and clogging mucous. Obviously how bad your lung disease is depends on how bad your CF is, but you still have some form.
Smoking leaves behind tar in your lungs. Lots of sticky stuff ontop of CF sticky stuff, just isn't good!
You've heard smokers hacking away with their cough right? That's because their lungs are trying to get rid of all the rubbish. The CF cough, is often mistaken by the general public with smokers cough. Can't even begin to imagine what a CF smokers cough sounds like!
Anyway, that's enough of my slating of smoking and CF. It's just not good, definately not advised, and in my opinion totally not worth the risk (though people of course have their own opinions on this.)
It's good to hear that you're well enough to jog everyday. Keep up that excercise!!!:D