They have also made him an offer for a longer term deal.
Currently injured, Naughton has been in fine form for the Airlie Birds this season.
“Curtis has really taken to the club and has been brilliant for us, on and off the field,” said Hull coach Lee Radford.
“He has had to wait patiently for his opportunity but continued to push really hard for a chance and when it came he took it with both hands.
“His debut against St. Helens was outstanding, particularly in the circumstances and he has backed that up with some good performances since then.
“He can play on the wing or full back which gives us some options and has proven this year that he wants a spot in the side and wants to keep it.”
The news comes on the same day as Tom Lineham‘s move to Warrington in 2016 was confirmed.
Radford revealed that Naughton was something of a gamble when the club signed the former Bradford junior from Sydney Roosters at the start of the season.
“When we first looked at signing him a few people warned us off him, but we did our homework, gave him a chance and he has been terrific,” said the Hull coach.
“He likes the club, the environment and is popular among the playing group.
“It was a very easy decision to make to extend his deal and we’ve offered him the security of a few extra years too.
“We’re looking forward to seeing him continue to grow and make real an impact at the club.”