Ethereum delays Glamsterdam’s Hoodi testnet rollout

The Ethereum Foundation said developers postponed the rollout to investigate how two Glamsterdam proposals interact with smart contracts already deployed on Ethereum. The delay creates uncertainty over the hard fork’s mainnet schedule, which developers had been considering for early December after successful Hoodi testing.

The concerns involve EIP-8037 and EIP-8038. On Oct. 13, blockchain security firm ChainSecurity warned that the proposals could weaken safeguards against insufficient gas griefing. In this type of attack, a caller provides too little gas for a legitimate smart contract operation to finish.

Under the proposed gas rules, gas could be returned to a contract after an operation fails. The contract could then continue running when it would previously have stopped. ChainSecurity warned that this change could interfere with security checks that use the amount of remaining gas to determine whether an operation succeeded.

An affected contract could permanently record a failed operation. For example, it could remove a user’s claim or prevent the user from retrying the operation, even though the transaction was valid. ChainSecurity said the changes would not make every gas-related security check unreliable, but developers would need to review existing safeguards under the new rules.

In an Oct. 21 GitHub comment, pseudonymous security researcher pcaversaccio described the risks as “serious” and called for the proposed hard fork to be reassessed.

On Oct. 23, ChainSecurity said it had identified 13 real-world examples of potentially affected contracts and was coordinating responsible disclosure with the projects involved. The firm did not identify the projects or disclose details of the examples. It urged developers to review their contracts as soon as possible.

The concerns follow an earlier warning from the Ethereum Foundation that Glamsterdam’s revised gas model could disrupt wallets, blockchain indexers and gas-estimation tools that rely on fixed assumptions. The upgrade was activated on the Sepolia testnet on Oct. 6. Developers are expected to set the mainnet schedule after further testing and review.