About 40 firefighters responded to the 3,500-square-foot house on Shea Ridge around 1:45 a.m.
A Porsche and Mercedes were destroyed and an additional two vehicles in the driveway sustained major damage.
According to Orange County Fire Authority Capt. Steve Concialdi, two bedrooms above the attached garage sustained some fire and smoke damage.
Six adults were inside the house when the blaze started. All managed to get out safely.
No injuries were reported.
The cause of the fire remains unknown but investigators say it likely started in the garage.
CNS contributed to this report.