In Mid August 2021, the crypto world witnessed a major incident, where Ethereum Blockchain nodes split from the main network. The cause was a bug that effected older versions of Ethereum. Around 54% of Ethereum nodes were affected.
A bug in older versions of the Ethereum network client Geth has caused nodes running those versions to split from the main network. The bug impacts older versions of Geth clients, specifically v1.10.7 and earlier. These make up nearly 75% of all Ethereum nodes, and 73% of Geth clients are still running the older versions.
Many were concerned that this would lead to double spending attacks, where crypto is spent but then the transaction is overwritten by the alternative chain. According to Block Research The bug, which has the potential to impact other EVM-compatible chains, has also been exploited on Binance Smart Chain by this address and on Huobi ECO Chain by this address (H/t Peckshield). It does not appear to have been exploited on Polygon.
So far no huge ramifications have occurred as the majority of miners are running updated versions of Ethereum, which means hashrate is supporting the longest chain. However nodes running on older versions of Geth cant access the main network.
This bug was found in an audit of Telos EVM, the version of the Ethereum Virtual Machine running on the Telos blockchain, according to a press release. Guido Vranken, auditor at Sentnl, which carried out the audit, found the bug, calling it a “high severity issue.” After Ethereum core developers were informed about the issue, they released a patch on August 24 to fix it. But this only helps those who have upgraded their nodes.
Ethereum has split into at least 2 versions and only a third of Geth nodes are in the ‘correct’ chain. The full impact is unclear at this point, but Openethereum may have also been indirectly impacted. Block difficulty has dropped 10% over the past few hours.
The founder of Yearn Finance, Andre Cronje, also discussed the situation on Twitter. “Fork between latest Geth and older Geth on mainnet,” Cronje said. “Stay away from doing [transactions] for a while till confirmed, unless you are sure you are submitting to latest Geth. Go for a walk outside, we all need it.”
Earlier this August Ethereum activated its London Fork which was successful. Rather than holding a blind auction every block to determine the gas price, ethereum’s protocol will algorithmically decide the transaction fee based upon overall demand on the network. The fork coincided with a runup in the price of ether, the native token of ethereum’s blockchain. The cryptocurrency was at $2,620, up 3.9%.
The Ethereum network has suffered similar forks in the past as well, for example earlier thsi year when clients could not sync to the network due to an error, or in November 2020 when again Geth users failed to update their nodes following a key update.
The latest Bug Fork debacle has not affected the price of Ethereum much. The price is 3,159 only 3 percent down this week. As long as no adverse consequences arise, it seems this incident will pass and Ethereum will continue to grow.