The stability problems of a multilayered bodies with a damaged contact of materials are considered in the exact formulation of the three-dimensional linearized stability theory of deformable bodies. The opening of the interface crack is taken as the stability loss of the composite. Using integral Fourier transforms, the problems are reduced to a system of homogeneous Cauchy-type singular integral equations of the second kind with additional conditions. The buckling load is found numerically: using the Gauss-Chebyshev integral formula the eigenvalue problem is reduced to a system of 2n homogeneous algebraic equations with 2n unknown values of functions of displacement perturbations. The dependences of the critical load on the geometric and physical parameters of the composite materials are analyzed.