Ethereum infrastructure firm Nethermind has fixed a “critical” bug in several versions of its execution client that reportedly caused users to fail to process blocks on Ethereum.

While the situation affected the users of Nethermind, a minority client, the incident has led some Ethereum community members to reiterate the importance of diversifying away from the majority client, Geth.

The latest hotfix addresses a consensus issue in Nethermind that had been introduced in version 1.23.0, according to a Jan. 21 post on Nethermind’s GitHub account.

Nethermind co-chief technology officer Daniel Cadela confirmed that versions 1.23-1.25 were impacted and called on node validators to update to version 1.25.2. Cadela described  the bug as “critical” in his follow-up post.

We have the fix!
Please update to 1.25.2
No resync is needed. https://t.co/fV3MEdipVX …
Versions up to 1.22 don't have that bug, only 1.23-1.25 are affected.

— DanielC (@_D4nie1_) January 21, 2024

The issue was first voiced by GitHub user “wga22” who reported  their Nethermind execution client was no longer processing blocks.

The new version 1.25.2 ca approximately 2.5 hours after the firm’s technical lead Lukasz Rozmej said the firm was investigating the issue.

At first glance, Ethereum advocate Superphiz referred to the dilemma as “no big deal” so long as the consensus issue only impacted minority clients.

“As a matter of fact, it's a very deliberate design decision not to rely on any single point of failure,” Superphiz added.

I just heard about a potential client bug in Nethermind. This is no big deal as long as it only affects minority clients - as a matter of fact, it's a very deliberate design decision not to rely on any single point of failure. https://t.co/HrjtsG4ckw

— superphiz.eth ️ (@superphiz) January 21, 2024

However, several members of the Ethereum community argued the situation could’ve been much more damaging had the issue come about in Geth — which currently accounts for 84% of execution clients on Ethereum.

“Today's beacon chain hiccup has once again highlighted the importance of EL client diversity,” explained Ethereum advocate “daddysether” in a Jan. 21 post.

“Switch to a minority client, and help keep Ethereum secure!” they added.

Related: Ethereum devs air concern over Vitalik’s plan to increase gas limit

Nethermind currently only accounts for 8.2% of execution clients on Ethereum, data shows.

However, in August, Ethereum bull Anthony Sassano shared a screenshot that showed a much healthier execution client diversity, with Geth and Nethermind accounting for 48% and 26% of execution clients, respectively.

“Client diversity is one of the Ethereum ecosystems greatest achievements,” Sassano said at the time.

The increased reliance on Geth now has several members of the Ethereum community worried.

“Nothing against Geth (they're great) but you're taking on disproportionate risk by running it,” said Ethereum advocate “marceaueth” on Jan. 21.

Look y'all

Besu had an issue earlier this month. It wasn't a big deal cuz they're ~4% of the network

Nethermind has an issue today. It's not a big deal cuz they're ~10% of the network

Client bugs can happen IN ANY CLIENT. Geth could be next. It would be a big deal https://t.co/MxbWpxlFQR

— nixo.eth (@nixorokish) January 21, 2024

Magazine: Ethereum restaking: Blockchain innovation or dangerous house of cards?