It could be a failure of an airbag system component, OR just a "glitch" that needs to be reset. If it "just happened" it could be a true failure. If it happened in conjunction with a dead/replaced battery, jump start, etc. it could be just a computer glitch.
Either way, the only way to find out is to have the code scanned and reset. The dealer can do it, or you can buy the airbag scanner tool from
www.peakeresearch.com for $129. Note: an OBD scanner WILL NOT read/reset the airbag computer.