The 18-year-old is a much wanted man this summer.
He was involved with the Sunderland first team, and was wanted by other clubs.
But Norwich have stolen a march on other clubs to seal a deal for Mumba, per the Daily Mail.
The player only has a year left on his contract, and Sunderland do not want to lose him on a free next summer.
Any fee would include performance related add-ons, and may rise above a basic £500,000.