The Toronto Maple Leafs are just under two million dollars over the salary cap.
In the NHL, you can be over the salary cap by up to 10% during the off-season, so this is not an immediate problem for the Toronto Maple Leafs, but one that they eventually will have to deal with.
The Leafs may be maxed out, but they are one of the best teams in the league, and they have spent their money wisely and so they have a lot of options for proceeding from here.
The Leafs have Jake Muzzin, Alex Kerfoot, Justin Holl, and TJ Brodie making a combined $16 million dollars.