Glamsterdam Takes a Gas Break: Hoodi Upgrade Delayed Over Contract Risks

Ethereum core developers postponed the Glamsterdam upgrade on the Hoodi testnet, canceling its October 26, 2026 activation after ChainSecurity identified gas-accounting and smart-contract security risks associated with EIP-8037 and EIP-8038. No replacement Hoodi date has been set, while Ethereum’s mainnet schedule remains undecided.

The decision was made during All Core Devs Execution (ACDE) call #248. The postponement removes the Amsterdam execution-layer activation, the Gloas consensus-layer activation and the planned increase of Hoodi’s gas limit to 200 million from the October 26 epoch. The Glamsterdam configuration has been rolled back for a future date, with a revised schedule to be announced separately.

On Oct. 13, ChainSecurity warned that the proposed rules could return gas to a contract after an operation fails, allowing it to continue running when it previously would have stopped. Researchers said this could interfere with safeguards against insufficient gas griefing, in which a malicious caller provides too little gas for a legitimate smart-contract operation. Affected contracts could permanently record failed operations, including removing a user’s claim or disabling the option to retry it, although some safeguards could remain functional with additional review.

Concerns were reinforced in an Oct. 21 GitHub comment from pseudonymous security researcher pcaversaccio, who described the risks as “serious” and called for a reassessment of the hard fork. On Friday, ChainSecurity said it had identified “13 real-world examples” and was coordinating responsible disclosure with affected projects. The firm did not identify the projects or disclose details of the examples, but urged developers to check their contracts as soon as possible. An earlier Ethereum Foundation warning said Glamsterdam’s gas model could break wallets, indexers and gas estimators that rely on fixed assumptions.

On October 23, 2026, lenny 🥷 (@blockchainlenny) wrote: “Ethereum postpones the Glamsterdam upgrade and cancels Monday's Hoodi testnet activation after security developers flagged risks to existing contracts. Just another reminder that protocol upgrades can be fragile.”

Glamsterdam was previously activated on Sepolia on Oct. 6. Developers had been considering early December for the mainnet release, pending successful Hoodi testing, while the Q4 2026 mainnet window remains open with December as a candidate. No action is required from mainnet users or $ETH holders, while node operators must update their clients and contract developers were urged to review their gas assumptions.