Speculation is running right now on why Mario Kart 8 for the Wii U console and the original Splatoon game cannot connect to their multiplayer servers as Nintendo is running maintenance and how long it has taken.
There is no good news.
Nintendo has still to acknowledge it is wrong with both Wii U games Mario Kart 8 and Splatoon as they have been disconnected for maintenance since last night but no signal on when the game will have their multiplayer service back.
While some have attributed this to Nintendo 's evident desire to sunset Wii U platform entirely, the reason appears to be something quite different.
The probable main culprit is an exploit known as ENLBufferPwn, which allows an attacker to take over someone’s console and execute code on it, just by playing against them online.
Mario Kart 7 for Nintendo DS and Mario Kart 8 Deluxe for the Nintendo Switch were also affected but Nintendo already patches both games to be ENLBufferPwn-proof, but apparently Nintendo might just have identified the exploit being used on Wii U.
The danger of the exploit is that it could be used to steal credit card information from the Nintendo eShop.