An assembly for a vehicle includes a vehicle pillar. The assembly includes a vehicle door adjacent the vehicle pillar. The assembly includes an airbag supported by the vehicle door. The airbag includes an upper portion inflatable upwardly and a lower portion inflatable downwardly. The assembly includes a pyrotechnic device supported by the vehicle pillar. The assembly includes a cable extending along the vehicle pillar from the pyrotechnic device and coupling the upper portion of the airbag to the pyrotechnic device.