Seven inmates were evacuated and the fire brigade called after six cell fires at HMP Northumberland in Acklington last Thursday.
Violence broke out in the exercise yard following the evacuation, but the inmates surrendered after extra officers were deployed.
Sodexo, which runs the prison, confirmed the incident took place.
It is not known how the fires broke out, but they were put out by firefighters.
Six of the seven prisoners were later relocated to other jails.
The category C prison has been criticised by MPs and union officials for a series of incidents in the last year, including a stand-off in which inmates took control of a whole wing.
The prison was privatised last December, before Sodexo laid off about 200 staff.
A company spokesman said: "We can confirm there was an incident involving seven prisoners at HMP Northumberland on Thursday night (27 November).
"Prison staff resolved the situation within a few hours."
Prisoners ran riot after fire broke out at a north-east England jail, BBC News understands.