According to EuroGamer, new PSN-enabled custom firmware was recently released for hacked consoles, which was subsequently followed up by publication of the console's LV0 decryption keys.
Custom firmware used to be a rampant part of the underground PS3 scene, but after Sony radically beefed up security, it has become a very rare thing.
"The release of the new custom firmware - and the LV0 decryption keys in particular - poses serious issues," explained EuroGamer's Richard Leadbetter. "While Sony will almost certainly change the PSN passphrase once again in the upcoming 4.30 update, the reveal of the LV0 key basically means that any system update released by Sony going forward can be decrypted with little or no effort whatsoever."
Interestingly, the issue was highlighted by a Chinese hacking group BlueDiskCFW, which obviously doesn't have the best intentions in the world, as it planned to sell the custom firmware. The group said it found the hack a while ago but "the fear of our work being used by others to make money out of it has forced us to release this now."