A major consensus bug has affected more than half the Ethereum network’s nodes, causing those running older versions of Geth to split from the main network.
According to Ethereum software developer Marius van der Wijden, an unknown individual or group exploited a vulnerability affecting earlier versions of Geth, one of Ethereum's software clients. According to the developer, Geth clients and Ethereum nodes running software v1.10.7 or earlier are at risk of splitting from the network.