Kent Police said three or four men entered the property at around 1am on Wednesday, October 31.
It is alleged the intruders assaulted the victim and he received injuries to his shoulder and left arm that are consistent with a stabbing. The men then left the house and ran from the scene.
Investigating officer, Detective Sergeant Tom Daveney said: “I want to reassure residents that we believe this to be an isolated incident and Rusthall remains a safe place to live.
“We have been carrying out enquiries in the area and are seeking to establish the identities of the suspects. They are described as wearing dark clothes and balaclavas.”
The victim’s injuries are described as non-life threatening.
If you have any information, please call Kent Police’s appeal line on 01622 604100.