Sealing system of a device for allowing the passage of a medium, in particular in the high pressure range, is provided with a housing that has a bore hole, a component mounted within the housing such as to oscillate and/or rotate and with a pressure chamber formed within the bore hole. A sealing element surrounding the component adjoins this pressure chamber which can be charged with the medium. An additional metal seal is formed here by the housing and a pressure disc surrounding the component. The outer region is thus tightly closed after the sealing element. In this way, the sealing element is completely tightly encapsulated on the outside.