  We report the existence of vectorial dark dissipative solitons in optical
cavities subject to a coherently injected beam. We assume that the resonator is
operating in a normal dispersion regime far from any modulational instability.
We show that the vectorial front locking mechanism allows for the stabilisation
of dark dissipative structures. These structures differ by their temporal
duration and their state of polarization. We characterize them by constructing
their heteroclinic snaking bifurcation diagram showing evidence of
multistability within a finite range of the control parameter.
