Suppose we have two identical ideal diodes (without any resistance or voltage drop). We connect these two diodes in series, in the same direction, and reverse-bias them with voltage V. Now we have two series reverse-biased ideal diodes. There isn't any other element in the circuit.
What is the voltage value at the node between the diodes? Maybe one would say V/2 because of the symmetry, but any answer between 0 and V cannot be refuted. A reverse-biased diode can (ideally) have any voltage.