Abstract:We compute the two-loop master integrals required for the leading QCD corrections to the interaction vertex of a massive neutral boson X 0 , e.g. H, Z or γ * , with a pair of W bosons, mediated by a SU(2) L quark doublet composed of one massive and one massless flavor. All the external legs are allowed to have arbitrary invariant masses. The Magnus exponential is employed to identify a set of master integrals that, around d = 4 space-time dimensions, obey a canonical system of differential equations. The canonical master integrals are given as a Taylor series in = (4 − d)/2, up to order four, with coefficients written as combination of Goncharov polylogarithms, respectively up to weight four. In the context of the Standard Model, our results are relevant for the mixed EW-QCD corrections to the Higgs decay to a W pair, as well as to the production channels obtained by crossing, and to the triple gauge boson vertices ZW W and γ * W W .