One appliance and crew from Beaconsfield and two from High Wycombe attended, along with an officer.
One car was well alight on the hard shoulder of the motorway. The incident generated multiple calls to Thames Valley Fire Control Service.
The firefighters used one set of breathing apparatus and one hose reel.
One lane of the carriageway was closed while they worked at the scene.
Thames Valley Police, and National Highways also attended.
