A firework set off inside a car is thought to have started a blaze which left the vehicle "extensively damaged".
The incident happened on Hillview Crescent in Annan at about 23:20 on Sunday.
There were reports of a "loud explosion" in the area when the black Vauxhall Astra caught fire.
Police said the owner put out the flames but not before the vehicle had been badly damaged as a result of the incident.
PC Ross Hair said: "It appears from early inquiries that a firework may have been set off inside the vehicle causing the fire.
"The consequences of this reckless act could have been so much worse had the fire not been tackled at an early stage."
He asked anyone who saw anything suspicious in the area at the time to get in touch.