A variable length endovascular prosthesis to prevent endoleaks includes a substantially tubular first graft member having an interior surface, an exterior surface, and an open end, and a substantially tubular second graft member engaged coaxially within the first graft member, the second graft member having a proximal end. The prosthesis further includes a substantially tubular fluid-tight connecting member attached at one end to the first graft member and attached at another end to the second graft member, where the connecting member is axially compressible and expandable to facilitate engagement of the proximal end of the second graft member within the first graft member while maintaining a seal between the proximal end of the second graft member and the open end of the first graft member.