Ethereum Glamsterdam upgrade set for Sepolia testnet on Oct 6; developers warn of potential builder-led disruption

Ethereum core developers have scheduled the Glamsterdam upgrade for its first public test on the Sepolia testnet on October 6, with a tentative follow-up on the Hoodi testnet on October 27. Developers warned that the upgrade's reliance on block builders could lead to network paralysis on testnets, as attackers could use free testnet ETH and fake identities to win block auctions without delivering transaction data. While this vulnerability is limited to testnets and poses no risk to mainnet funds, it could hinder the testing process and delay the upgrade's timeline. Client teams are required to release Sepolia-ready versions by September 29, leaving only a seven-day window for security reviews, half the standard duration. The mainnet launch date remains undecided.