An airbag includes a first panel having a perimeter, and a second panel connected to the first panel along the perimeter of the first panel. The first panel and the second panel define an inflation chamber between the first and second panels. The first panel has a tab extending from the perimeter of the first panel and transverse to the perimeter of the first panel. The tab is connected to the second panel. A vent on the tab is in communication with the inflation chamber.