We consider the Creutz ladder model, a quasi-one-dimensional fermionic system which supports zero-energy modes locked to open ends. Augmenting the model with induced s-wave pairing can lead to a topological superconductor with zero-energy Majorana bound states at the edges, or a trivial superconductor with chiral bound states at the edges. We investigate the stability of these phases in the presence of Hubbard repulsive interactions with matrix-product-state density matrix renormalization group and mean-field theory. We show how interactions remove the accidental zero-energy modes, while leaving the Majorana bound states intact.