Ethereum Developer: Attackers Can Win Sepolia Block Auctions with Free Testnet ETH and Withhold Transaction Payloads

Ethereum developers warn that attackers could exploit free testnet ETH and one-time builder identities to win Sepolia block auctions during the Glamsterdam testing period and withhold transaction payloads. The attack does not threaten mainnet funds but could disrupt infrastructure testing. Sepolia public testing is scheduled to launch on October 6, with Hoodi testing tentatively set for October 27, while the mainnet activation timeline remains undetermined.