Adjusting element having a cylinder with pressure relief

A cylinder has an interior space which contains a medium under pressure. A piston is displaceably arranged in the cylinder and has a piston rod which projects from the cylinder at one end of the cylinder. The piston rod is enclosed by an annular seal having an inner radially encircling circumference which bears against the piston rod and an outer radially encircling circumference which bears against the inner wall of the cylinder, a side facing the interior space to which the pressure of the medium is applied, and a side remote from the interior space supported on a supporting element. The supporting element, in turn, is supported on part of the cylinder. The supporting element includes a safety element which is designed to shorten its axial length during thermal overloading, as a result of which a passage opens from the interior space of the cylinder to the environment. The safety element is made of a melting or subliming material.