Significant Decline in Ethereum Validator Participation
After the Fusaka network upgrade, Ethereum has experienced a 25% decrease in validator voting participation due to a Prysm consensus client bug, putting it dangerously close to losing finality.
Details of the Incident
Prysm reported that its version v7.0.0 was generating old states while processing outdated attestations. This flaw, as highlighted by Terence Tsao, the core developer, hindered the client nodes from operating correctly.
To mitigate the issue temporarily, developers suggested using the --disable-last-epoch-targets flag when launching the client. During epoch 411,448, only 75% sync participation was achieved, indicating a 25% drop in voting participation, just shy of the two-thirds supermajority needed to maintain finality.
At present, the network has recuperated to nearly 99% voting participation in the current epoch 411,712. However, the decline in voting was notably linked to the percentage of validators employing the Prysm client, which fell from 22.71% to 18% after the glitch.
Implications of Reduced Voting Participation
If the voting participation lowers below two-thirds, the Ethereum network is at risk of losing finality. This would freeze layer-2 bridges and halt rollups, leading to heightened risks in block confirmations across various exchanges.
In early May 2023, Ethereum’s mainnet faced a similar finality loss, further demonstrating the precariousness of the network’s client diversity.
Importance of Client Diversity
Despite gradual improvements in client diversity since 2022, the security threshold of under 33% has not yet been achieved. As per recent statistics, Lighthouse dominates, comprising 52.55% of consensus nodes, whereas Prysm has seen a drop to 18%.
Anthony Sassano mentioned that had Lighthouse experienced a similar bug, it could have resulted in the same finality loss.
“If Lighthouse had had the bug instead, then the network would’ve lost finalization.”
Translation: “Si Lighthouse hubiese tenido el error en su lugar, entonces la red habría perdido la finalización.”
