As we know light travels as an electromagnetic wave...but electric fields and magnetic fields are interactions between charges...they are the forces acting on stationary and moving charges respectively. But when there is no charge how can these fields propagate through free space??
Charges are the source of electromagnetic waves, not the medium that the waves travel through.
As an analogy, say you're on a boat on a lake, and another boat moves past. The waves from the wake of the other boat will make your boat rock. That's an interaction between the other boat and your boat caused by the water waves produced by the other boat.
But there didn't have to be any other boats between your two boats for the wave to reach you.