The Prysm development team recently released an after-action report detailing the mainnet anomaly event that occurred after the Fusaka upgrade on December 4, 2025. The issue once threatened the stability of the Ethereum network but was ultimately mitigated thanks to the diversity mechanism of clients.
The report shows that the problem occurred at epoch 411,392 (December 4, 21:49 UTC) after the Fusaka upgrade was activated. Prysm consensus clients triggered a large amount of repeated calculations of historical states when processing specific proof data, leading to rapid exhaustion of CPU and memory resources, causing nodes to experience denial-of-service (DoS)-type performance degradation. This was not a protocol design flaw but an implementation issue within the client under certain boundary conditions.
Affected Prysm validator nodes accounted for approximately 15% to 22.71% of the network. During the event, overall validator participation rate plummeted from normally over 95% to about 75%, resulting in the network missing 41 consecutive epochs, leading to a loss of about 382 ETH in attestation rewards and approaching finality loss. Prysm core developer Terence Tsao pointed out that the computational load of replaying historical states was extremely high, and multi-threaded parallel triggering significantly slowed node performance.
It is worth noting that the Fusaka upgrade itself was successful. The upgrade introduced PeerDAS (Peer Data Availability Sampling) technology, aiming to increase Layer 2 blob capacity by eight times. The upgrade process involved no downtime or consensus forks.
The reason the Ethereum network avoided more severe consequences was due to client diversity. Besides Prysm, ten other consensus clients such as Lighthouse, Teku, and Nimbus remained functioning normally throughout the process, allowing approximately 75% to 85% of validators to stay online and ensuring the network’s finality was not compromised. If a similar issue had occurred with a higher proportion of clients, the consequences could have been more severe, including suspension of Layer 2 aggregations and validator withdrawal blocks.
After the incident, the Ethereum Foundation quickly issued emergency guidelines. The Prysm team deployed temporary runtime fixes first and released permanent solutions in versions v7.0.1 and v7.1.0. By December 5, the network participation rate had recovered to nearly 99%, and the Ethereum mainnet fully resumed normal operation within 24 hours.
Disclaimer: The information on this page may come from third parties and does not represent the views or opinions of Gate. The content displayed on this page is for reference only and does not constitute any financial, investment, or legal advice. Gate does not guarantee the accuracy or completeness of the information and shall not be liable for any losses arising from the use of this information. Virtual asset investments carry high risks and are subject to significant price volatility. You may lose all of your invested principal. Please fully understand the relevant risks and make prudent decisions based on your own financial situation and risk tolerance. For details, please refer to
Disclaimer.
Related Articles
Citigroup Slashes Bitcoin and Ethereum 12-Month Price Targets, Citing Stalled U.S. Crypto Legislation Weighing on Upside Catalysts
Citigroup has lowered its 12-month price targets for Bitcoin and Ethereum, signaling a shift toward caution on the cryptocurrency market's medium-term outlook, primarily due to slow progress in U.S. crypto asset legislation. Bitcoin's target was reduced from $143,000 to $112,000, while Ethereum's fell to $3,175. Despite upside potential remaining in the future, the lack of new policy catalysts suggests prices may oscillate within a range in the near term. Citigroup's assessment of Ethereum is more cautious, as it believes the asset is more significantly impacted by on-chain activity.
区块客17m ago
ShapeShift Era Mysterious Whale Continues ETH Accumulation with $4.35M USDT Purchase
Gate News bot message, a mysterious whale from the ShapeShift era has withdrawn $4.35M USDT from Aave and purchased 2,103 ETH. The whale now holds 122,392 ETH worth $251.3M.
According to Onchain Lens, this whale previously withdrew $4.29M USDT from Aave and bought 2,012 ETH, bringing their total h
GateNews20m ago
NYSE Cancels Crypto ETF Options Position Limit of 25,000 Contracts, SEC Exempts 30-Day Waiting Period
NYSE Arca and NYSE American, subsidiaries of the New York Stock Exchange, have submitted rule changes to the SEC to eliminate position limits on spot Bitcoin and Ethereum ETF options, effective immediately. This change affects 11 cryptocurrency ETFs and allows large, liquid ETFs to have higher position limits. Meanwhile, Nasdaq ISE has proposed increasing the position limit for IBIT exclusive options to 1 million contracts, pending review.
GateNews25m ago
The Hormuz Strait crisis remains unresolved, and Bitcoin has fallen below 68K.
Affected by the US-Iran conflict, global markets have been severely impacted, with the S&P 500 Index declining for four consecutive weeks. Gold has experienced a modest rebound around $4,500, while oil prices remain stable at elevated levels. Trump has issued an ultimatum to Iran, with potential escalation of conflict between the two sides. Bitcoin and Ethereum have also declined in tandem, and market sentiment has turned conservative.
ChainNewsAbmedia34m ago
Ethereum At the Crossroads – Breaking 0.03250 BTC Is the Key to Reigniting the Altcoin Bull Market
The current state of the crypto marketplace is marked by a profound sense of uncertainty. This state has often been referred to as “no man’s land,” and Bitcoin has consistently been the coin that elevates all others. However, at this moment, the dynamic between Bitcoin and Ethereum, is
BlockChainReporter34m ago
ETH 15-Minute Rally of 0.81%: Whale Large Withdrawals Combined with Exchange Liquidity Plunge Driving Surge
2026-03-22 22:15 to 22:30 (UTC), ETH recorded a +0.81% return rate within 15 minutes, with a price range of 2041.49 - 2064.99 USDT and a volatility amplitude of 1.15%. Market attention increased rapidly, intraday fluctuations intensified significantly, and some investors focused on large on-chain transfer activities.
The main driver of this price movement was whale wallets cumulatively withdrawing approximately $155 million in ETH from major exchanges within 48 hours, significantly reducing the available trading liquidity on exchanges. On-chain data shows that some large amounts of ETH flowed into
GateNews2h ago
