The 19-year-old Academy graduate, a first-year professional, made his senior debut for the League One club in November and five appearances have since followed, including three starts.
Manager Dean Smith said: "Mal is a great prospect for this club. I have known him since he was an Under-15 player here and he has just got better and better during that time.
"He has taken the opportunity that has been given to him and showed that he can handle playing at this level.
"This new deal gives him a great chance to continue that progression; he has a fantastic attitude and I know that he will continue to work hard at his game. He's another real talent to come off the production line here."
Singh Benning added: "At the start of the season I wanted to establish myself and do well for the reserves, but things have gone really well so far and to get my chance in the first team at this stage of my career has exceeded my expectations."