why does my chrysler 300crd randomly send exhaust fumes into the cabin of my car

You may have en exhaust leak, you can look at it yourself and look for exhaust gasses or water dripping from a weld spot. or find a good local exhaust shop and take it there they can usually fix it cheap.

You most likely have an exhaust leak, take it to an exhaust shop and have it checked out.

I have the same problem. Can see the fumes coming out of the rear of the bonnet (hood) and being sucked into the cabin vents to the interior. It usually stops after about 1 minute, but then the car stinks for ages. It is random, it might not do it for a month of driving, then does it several times a day.