A vial stopper for closure of a lyophilization vial is disclosed. The vial stopper has a stopper body comprising a first circumferential sealing surface for hermetically sealing against an interior surface of a mouth of the vial in a first position of the vial stopper. The stopper body further comprises a second circumferential sealing surface for hermetically sealing against the interior surface of the mouth of the vial in a second position of the vial stopper. The second sealing surface is spaced apart from the first sealing surface in an axial direction of the stopper body. The stopper body further comprises an intermediate region in between the first and second sealing surfaces, the intermediate region having at least one venting element for venting an interior of the vial in at least one intermediate position of the stopper in between the first and second positions.