If it's leaking at the front, then it's likely the drain tube from the sunroof. Not common, but it has been known to happen that the tube is not connected at the factory.
If it's leaking at the back, that is more common, and is likely coming in at the High Level Brake Light. When it's here, often the back storage compartments under the back seat will fill with water.
Either way, your dealer will take care of it. I am not aware of anyone having any negative affects from either of these leak issues, other than the inconvenience at the time, so wouldn't fret about it too much. It's a bummer when this happens with a new vehicle, but stuff happens, and that is what warranty is for.