Bungie is naturally sad but also warns Halo fans it's probably best to avoid gaming sites if you want to remain "spoiler free" before it retails.
"Posting to Discuss, Request, or Link To information or campaign spoilers from illegitimately obtained sources - including illegitimately obtained copies of Halo: Reach - before the game is officially released will be considered a leak and will be treated as such," moderators on the official Bungie forum.
"The moderation team is doing their best, but if you want to stay 100 per cent spoiler free, our best advice is to 'go dark' by staying off all internet gaming forums until you have played through the game!" Halo: Reach releases on Xbox 360 September 14th.
The sci-fi prequel sequel was made available to the press for review via the Xbox Live Marketplace, with the 7GB title priced at 99999 MS Points. 'Code enthusiasts' bypassed Microsoft's stellar defence of awesome and nabbed copies for themselves.
"We are aware of claims being made regarding a security exploit related to Halo: Reach and are aggressively investigating the matter," Microsoft said. "We have no further details to share at this time." This is quite the embarrassment for the corporate giant.