TLDR
- Ethereum developers postponed the Glamsterdam upgrade on the Hoodi testnet, which was set for Oct. 26.
- Security firm ChainSecurity warned that new gas rules could let contracts permanently record failed operations.
- ChainSecurity found 13 real-world examples of contracts that may be affected and is coordinating disclosure.
- Glamsterdam finished its Sepolia testnet activation on Oct. 6.
- No new date has been set, and a mainnet launch in early December is now uncertain.
Ethereum developers have called off the Glamsterdam upgrade on the Hoodi test network. It was due to go live on Oct. 26 at 17:42:48 UTC. Researchers found a problem that could change how existing smart contracts handle failed transactions.
Ethereum Postpones Glamsterdam Upgrade on Hoodi Testnet Over EIP-8037 Compatibility Concerns
According to the Ethereum Foundation, Ethereum core developers have postponed the Glamsterdam upgrade on the Hoodi testnet, originally scheduled for October 26, to further investigate… pic.twitter.com/jwbZBiNEDV
— Wu Blockchain (@WuBlockchain) October 23, 2026
Developers made the decision during Thursday’s All Core Devs Execution meeting. They want time to study how a proposed change to gas accounting works with contracts already running on the main network. No replacement date has been announced.
What the Security Researchers Found
The concern centers on EIP-8037, which changes how Ethereum charges for creating new records in its database. The proposal aims to limit database growth as the network prepares to handle more transactions.
On Oct. 13, security firm ChainSecurity published an analysis of the change. It said EIP-8037, combined with EIP-8038, could alter how contracts react when another contract they call runs out of gas. Gas is the fee used to pay the network’s operators.
Some contracts are built to catch a failed operation and keep going. They may record the failure, disable more attempts or move to another step. Developers sometimes count on the remaining gas being too low for those actions, so the whole transaction reverses instead.
Glamsterdam changes that. Under the proposed rules, gas used to create certain records can be restored when those changes are undone. That may leave enough gas for a contract to finish a failure-handling step that would have reversed before.
ChainSecurity said this could weaken protection against insufficient gas griefing. In that type of attack, a malicious caller gives too little gas for a valid operation to succeed. An affected contract could remove a user’s claim or disable the option to retry it.
There is also a risk in the other direction. ChainSecurity calculated that creating a new storage slot could require 110,020 gas when a separate allowance runs out. Under the old rules, it was 22,100. A contract using an existing gas budget might fail during an otherwise valid operation.
Reaction and Next Steps
ChainSecurity said Glamsterdam would not make all gas-related security checks unreliable. Some safeguards could still work, but developers would need to review them against the new rules. The firm has shown how the problems could occur, but has not shown that a major production protocol can be exploited.
The findings drew concern from Ethereum contributors. In an Oct. 21 GitHub comment, security researcher pcaversaccio called the risks “serious” and asked for a reassessment of the hard fork.
The Ethereum Foundation had earlier warned that Glamsterdam’s gas model could break wallets, indexers and gas estimators that rely on fixed assumptions. Glamsterdam also brings a new system for choosing block builders and changes meant to support larger blocks.
Hoodi was the next public test after Sepolia. A planned increase of the Hoodi gas limit to 200 million has also been postponed.
Developers had been considering early December for the mainnet launch. They planned to set a schedule after successful Hoodi testing. On Friday, ChainSecurity said it identified 13 real-world examples of affected contracts and is working with those projects on responsible disclosure. It did not name them and urged developers to check their contracts soon.
