Hackers exploited a bug in the Elements software underlying the Liquid Network sidechain to withdraw nearly 4,000 bitcoin (~$320M) from its federation wallet on September 6. The following day, the group — claiming to be white hats — returned 3,400 bitcoin (~$265M) after Blockstream confirmed its nodes had been patched, but approximately 598.5 bitcoin (~$47M) remains unreturned. While Blockstream says it is still in contact with the group and is preparing to restart the network, critics such as Ledger's CTO have questioned the white-hat label, suggesting the retained funds may amount to extortion.
