An adjustable vibration damper, having a displacer in a cylinder, a damping medium exerting a damping force via an adjustable damping valve. The adjustable damping valve is activated by a control pressure of a pneumatic spring A safety device is provided which, in the event of a control pressure reduced as a result of damage to the pneumatic spring, provides a sufficiently high damping force of the vibration damper. At least two pneumatic springs are connected to the safety device, which is constructed from a pneumatic circuit functioning as a pressure balance between the pneumatic springs which releases the higher control pressure of a pneumatic spring in the pneumatic circuit. The adjustable vibration dampers which belong to the pneumatic springs are connected via at least one pressure outlet connection of the pneumatic circuit and are activated by the highest control pressure of the pneumatic springs involved.