Four days ago the Wii U was hacked by a group that goes by the name WiiKey. Since the system's launch they have been trying to break through the system's defenses. Early on they remarked that it shouldn't be long before homebrew makes its way to the system. They weren't kidding.
Today, the same group has dumped its first game: The Avengers Battle for Earth. They've published the download on the internet along with instructions allowing anybody who hates the gaming industry with the opportunity to stick their foot down Nintendo's throat.
Nintendo has taken the stance that it'll do everything in its power to thwart hackers. In the case of other consoles, many times that means making things more complicated for normal customers. But from the manufacturer's perspective, nothing is worse than angry third-party developers, and developers hate their games being pirated.
The Wii U already has one of the worst attachment rates in recent history, and piracy would only make it worse. The Wii was hacked early in its lifecycle prompting a dive in software sales and a rise in Craigslist ads for those looking to get their console modded.
Nintendo is currently on-track for its 12-month plan of making the Wii U an extremely competitive device with a 3D Mario among other potential system sellers on the horizon. Security issues make the battle much more challenging. This is the first next-gen system to be hacked, after all.