Ethereum developers have postponed the Glamsterdam upgrade on the Hoodi testnet, which had been scheduled for October 26. The decision was made to allow further investigation into how changes in gas accounting could interact with smart contracts already deployed on the network.

The postponement was confirmed during the All Core Devs Execution call. It cancels the planned activation of the Amsterdam execution-layer changes, the Gloas consensus-layer updates, and a related increase in Hoodi’s gas limit. No new testnet date has been set.

Security Concerns Raised by ChainSecurity

Blockchain security firm ChainSecurity published an analysis on October 13 examining two Ethereum Improvement Proposals included in Glamsterdam: EIP-8037 and EIP-8038. The firm found that the combined changes could alter how contracts handle situations in which gas is exhausted during a call.

Under the proposed rules, gas could be returned to a contract after a failed operation. This would allow execution to continue in cases where it previously would have stopped. ChainSecurity warned that the shift could weaken existing protections against a known attack pattern known as insufficient gas griefing.

In such attacks, a malicious party deliberately supplies too little gas so that a legitimate operation fails. The firm noted that the new behavior could allow failed operations to permanently change contract state, for example by removing a user’s claim or disabling a retry option.

The firm stressed that not every gas-related safeguard would become unreliable. Developers would still need to review their contracts to confirm that their logic accounts for the revised gas rules.

Developer Response and Timeline Impact

The findings prompted discussion among Ethereum contributors. Pseudonymous security researcher pcaversaccio described the risks as serious in an October 21 GitHub comment and called for a reassessment of the hard fork.

The Ethereum Foundation stated that the delay is intended to give teams time to examine how the proposals interact with contracts on mainnet. Glamsterdam had already activated on the Sepolia testnet on October 6. That deployment remains unaffected.

Developers had been targeting an early December mainnet window for Glamsterdam, with the final schedule expected after successful Hoodi testing. The testnet delay introduces uncertainty around that timeline. A revised Hoodi schedule is expected to be announced after further security reviews, potentially following Devcon in early November.

What the Upgrade Aims to Achieve

Glamsterdam is positioned as a major layer-1 scaling upgrade for 2026. It combines enshrined proposer-builder separation through EIP-7732, block-level access lists via EIP-7928, and the gas repricing changes under EIP-8037 and EIP-8038. The package is designed to increase throughput while managing state growth.

Node and validator operators will need to update clients such as Lodestar, Besu, and Nethermind to versions that remove the October 26 activation configuration. Mainnet users and ETH holders are not required to take any action at this stage.

The broader Ethereum roadmap continues, with later upgrades planned for subsequent years. The current pause applies only to the Hoodi testnet phase of Glamsterdam while the identified gas-related risks are examined in greater detail.