This paper considers the finite time path-following control problem for an underactuated surface vessel subject to parametric uncertainties, unknown disturbances, and involving input-control saturation. A finite time command filtered backstepping approach is adopted as the main control framework along with the first-order sliding mode differentiator introduced to compute the derivatives of virtual control laws, and the analytical computational burden in the backstepping control is reduced for the design of the control for the underactuated surface vessel. A rigorous proof of the finite time stability of the closed-loop system is derived by utilizing the Lyapunov method. Furthermore, in order to avoid obstacles, a local path replanning technique is designed based on a repulsive potential function that acts directly on the original desired path. The effectiveness of the proposed strategy is validated through numerical simulations.