Yellows8 released his Wii U browser exploit to the public after Nintendo rolled out an update which yellows assumed was to patch the browser exploit, turns out this was a mistake. Yellows says on his github:
"Originally this exploit was thought to be fixed via doing manual code-RE(hence why it was released when it was). However, that was actually wrong due to misreading that code: this exploit works fine as-is on 5.5.1(no testing on 5.5.1 was done before release, only code-RE)."
The conspirators in the scene believe that Nintendo have placed some timed code execution in the latest update 5.5.1 with the intention of duping Wii U owners into updating to the latest firmware in the belief that exploits still work. Once the masses have updated the timed code will silently patch the exploit.... This is not the case!
You can now go ahead and update to 5.5.1, thanks to yellows8 for his browser exploit.