Light scattering in a magnetic uncorrelated disordered medium is discussed in terms of polarization eigenchannels within the multiple scattering theory. The channels are characterized by individual transport constants: diffusion constant, attenuation coefficient, and free scattering path length. Leading-order magnetooptical effects induce oscillations in the subspace of linearly polarized eigenmodes. They appear in two pairs of modes with different frequencies. The subspace of circularly polarized eigenmodes remains free from magnetooptical effects.