The accident happened on Duff Avenue about 10:40 p.m. Friday, CHP Officer Anthony Martin said.
Police said it appears the woman hit the gas instead of the brake and smashed through a wall in the house, striking the boy and pinning the man under the vehicle.
"We did have to shore the vehicle, use cribbing, and then we used our high pressure air bags, as well as hand tools to lift the vehicle off the 40-year-old male," said L.A. County Fire Batt. Chief David Stone.
Police described the injuries as moderate to severe.
The mother was arrested on suspicion of driving under the influence.