Ravencoin said a critical consensus flaw was exploited, allowing invalid blocks to enter the proof-of-work network from height 4,487,776 and raising the risk of a multi-day rollback if a competing branch becomes dominant. The project said the first known invalid block appeared on Friday and warned that transactions confirmed after block 4,487,775 should be treated as at risk. Ravencoin said 2Miners and RavenMiner, which it said control a majority of the network's hash rate, are building an alternative chain that excludes the exploited branch. If that chain becomes the accepted record, the network could undergo a reorganization spanning roughly three days, reversing recent transactions and requiring some to be replayed. The project urged exchanges to suspend RVN deposits and withdrawals until the chain stabilizes because reversed transfers may not automatically return to the mempool or be mined again. Upbit and Bitget suspended RVN transfers after the disclosure, while Upbit kept trading open. RVN fell to a new all-time low of $0.002754 on Wednesday, about 22% below its 24-hour high of $0.003529, before recovering to around $0.00284. Trading volume rose above $18 million during the sell-off before easing to about $9.6 million. The episode underscores a familiar risk for smaller proof-of-work networks, where concentrated mining power and lower economic security can leave exchanges and other services exposed when invalid blocks are later removed from accepted chain history.