No medium is needed, because light belongs to electromagnetic waves, and the propagation of electromagnetic waves does not require a medium.
There is something mentioned in the physics book of the third year of high school: because the propagation of light does not require a medium, light is defined as an electromagnetic wave.
Sound is a material wave that requires a propagation medium. Moreover, sound is a longitudinal wave that can propagate in three states of matter: solid, liquid, and gas.
The transverse wave in the material wave can only propagate in the solid (it requires a large traction force). Please note: the water wave is not a transverse wave, it is a special kind of wave.
Light is a transverse wave (with polarization phenomenon) but it is also an electromagnetic wave. So no medium is needed.
Some of the concepts mentioned above are mentioned in the physics book of the third year of high school.