Depends on what has caused the crack, and how bad it is.
Have a good look around inside for any wear around the string holes on the bridgeplate. Sometimes, excessive wear round there can weaken the area and cause this problem. If that's the case, a patch up repair on the bridgeplate and either a replacement/glue up of the bridge could be the answer.
I wouldn't really like to tack a crack like that with the bridge on the instrument though, ideally remove the bridge and have a good look over it. Salvage if you can, replace if not.