The crash occurred at about 4:30 p.m. in the southbound lanes near the highway entrance ramp, fire Capt. Dave Zaniboni said.
He said the injured included four children, including three who were ejected from the vehicle.
Two children believed to be under the age of 10 suffered major injuries, Zaniboni said, as did the adult driver.
Another child suffered moderate injuries, and the fourth had minor injuries, he said.
One patient was later transported to a hospital in Northridge, according to the California Highway Patrol.
The names of the victims and their conditions were not available.
The crash is under investigation by the CHP.