One appliance and crew from Hertfordshire, one from Gerrards Cross and one from Amersham attended, along with an officer.
One of the cars had overtured onto its roof. Three men and two women were out of their vehicles when the firefighters arrived. No one was trapped. The firefighters provided immediate emergency care, before handing those injured into the care of South Central Ambulance Service.
Two of the lanes of the motorway were closed while they worked at the scene. The incident was left in the hands of Highways England.