Do you remember what year it happened and perhaps the forum? All mangas have majority of the plot already fully conceived and stored by shonen jump, it doesn't surprise me that those with access to SJ files manage to get the entire story.
I never heard about the naruto leaks, rlly spiked my curiosity right now
...Man that was so many years ago. I don't even know where to begin to find what forum it was or what I searched to stumble on it.
I remember the guy claimed his cousin or uncle or some branched off relative worked at Jump or with someone who worked at Jump, one of 'those stories,' and everyone told the guy he was BS. But his leaks said Itachi purposefully betrayed and was on the villages side, Madara was alive, and Naruto was the 4ths son. Of course, that entire thread ridiculed him. But then years later look where we are.