THORChain Paid Out 10 ETH It Never Received: The Reorg Bug That Could Happen Again

A one-block Ethereum reorg led THORChain to refund 10 ETH it never got. The protocol now warns that a reorg on any external chain could set off the same exploit. A deposit that no longer exists can still be refunded. That is what happened to THORChain on October 31, and the protocol itself says the same trick could work again. A One-Block Reorg Erases a Deposit According to THORChain's own account, the incident began at 11:34 UTC on Saturday, October 31. Ethereum went through a one-block reorganization, which happens when the network replaces a recent block with a competing one.