A gas injector for injecting a gaseous medium. The gas injector includes: a closing element which opens and closes a passage opening at a first sealing seat; an actuator for actuating the closing element; a restoring element for restoring the closing element; a second sealing seat which is located between a gas supply line connection and the first sealing seat in the flow direction of the gaseous medium and opens and closes a gas flow path in the gas injector; a vacuum connection which is located upstream of the second sealing seat in the flow direction of the gas injector; and a control valve which is fluidically connected to the vacuum connection and is designed to connect the vacuum connection to a vacuum source in order to open the second sealing seat.