Ethereum Network Hit by Chain Split Affecting Over Half of Nodes

14 2 min read Updated 2026-05-22
Highlights

The Ethereum network experienced a major chain split, affecting an estimated 54% of its operations.

The disruption occurred because a considerable number of validators were running older versions of the Geth client, which contained a critical bug.

This led to these nodes being disconnected from the main network.

The Ethereum network experienced a major chain split, affecting an estimated 54% of its operations. The disruption occurred because a considerable number of validators were running older versions of the Geth client, which contained a critical bug. This led to these nodes being disconnected from the main network.

Bug Exploited in Outdated Geth Clients

The vulnerability specifically targeted versions 1.10.1 and earlier of the Geth client software. Martin Swende, the Ethereum Foundation’s security lead, confirmed the incident via Twitter, noting that the bug had been fixed in Geth version 1.10.8. Fortunately, most miners had already updated their software, and the correct, longer chain prevailed.

Swende described the event as a “really close shave,” highlighting the potential for a significant fork impacting over half of Ethereum’s clients.

Past Incidents and Current Resolution

Chain splits are not entirely new to the Ethereum network, with a similar incident occurring in November 2020. In that instance, developers faced criticism for not issuing a more timely update, which could have prompted wider adoption and prevented the split.

This time, although the bug was identified a few days prior, not all miners promptly updated their software. However, major mining pools like Flexpool, BTC.com, and Binance were alerted and took swift action. While some experts advised a temporary pause on transactions via Geth clients, the threat of the chain split has largely subsided as validators update to the corrected software version.

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