  The most fundamental strings in high density color superconductivity are the
non-Abelian semi-superfluid strings which have color gauge flux tube but behave
as superfluid vortices in the energetic point of view. We show that in addition
to the usual translational zero modes, these vortices have normalizable
orientational zero modes in the internal space, associated with the
color-flavor locking symmetry broken in the presence of the strings. The
interaction among two parallel non-Abelian semi-superfluid strings is derived
for general relative orientational zero modes to show the universal repulsion.
This implies that the previously known superfluid vortices, formed by
spontaneously broken U(1)_B, are unstable to decay. Moreover, our result proves
the stability of color superconductors in the presence of external color gauge
fields.
