A lit firework was posted through a letterbox in South Tyneside at the weekend.
Police are appealing for information after the incident, which happened between 8.30pm and 9pm on Sunday in Church View, Boldon Colliery.
The firework caused minor damage to the property, but police are warning the consequences could have been far worse.
No one was injured.
Officers are carrying out enquiries and are appealing for witnesses.
Anyone with information should contact Northumbria Police on 101, quoting reference 998 061116, or Crimestoppers anonymously on 0800 555 111.