The crash happened around 3:15 a.m. at the intersection of Bloomfield and Canfield roads.
A man, a woman and two children at a home in the 2700 block of Canfield Road were awakened when the car, a 1993 Acura Legend, came crashing into their garage, CHP Officer Barbara Upham said.
The crash started a fire, which spread from the garage to the home's attic, kitchen and living room. Firefighters extinguished the blaze in about 30 minutes, Upham said. The home's residents escaped unharmed.
The driver of the Acura and a passenger were burned beyond recognition,, Upham said.
Upham said the Acura was traveling south on Bloomfield Road faster than the 40 mph speed limit when it left the roadway and struck multiple large boulders, a tree and then the door of the two-car garage. The house is set back from the road about 50-60 feet, Upham said.
A Ford F-150 pickup inside the garage also caught fire, Upham said.
The victims were taken to the Sonoma County coroner's office.
The car was registered to a San Jose resident and has not been reported stolen, Upham said.
Firefighters from Sebastopol, Gold Ridge, Graton and Cal Fire responded to the fire.