TLDR
- Ethereum developers delayed the Glamsterdam fork on the Hoodi testnet.
- ChainSecurity found eight smart contract assumptions that EIP-8037 and EIP-8038 could break.
- The Ethereum Foundation asked developers and auditors to report affected projects.
- Hoodi had been set for October 26, and no new date has been announced.
- Work on the next upgrade, Hegota, continues without delay.
Ethereum core developers have put the Glamsterdam upgrade on hold for the Hoodi testnet. The pause will last until security concerns tied to eight smart contract invariants are resolved. The Ethereum Foundation shared the update in a blog post on Nov. 6.
LATEST: ⚡ Ethereum developers say they are delaying the Glamsterdam hard fork process and won’t fork the Hoodi testnet until gas-repricing issues flagged by ChainSecurity are resolved. pic.twitter.com/7HDv6dZDrc
— CoinMarketCap (@CoinMarketCap) November 6, 2026
An invariant is a condition that a smart contract expects to always be true. Some existing projects assume that certain operations will cost a set amount of gas. Two Glamsterdam proposals change how gas is charged, which could make those assumptions wrong.
What ChainSecurity Found
The concerns come from an Oct. 13 report by smart contract auditor ChainSecurity. It looked at how Glamsterdam could change contracts that keep running after an external call fails. The report covers EIP-8037 and EIP-8038.
EIP-8037 changes the cost of creating new blockchain state. EIP-8038 changes the charges for accessing existing state. Both alter gas accounting for certain operations.
Under today’s rules, some contracts count on a failed operation leaving too little gas for the next steps. Under the new rules, certain operations could finish even when developers expected the whole transaction to revert. That could weaken safeguards built into those contracts.
ChainSecurity gave one example. A contract marks an operation as failed after an external call runs out of gas. With the new rules, gas that was once out of reach could become available again, and the contract could record a permanent failure.
The Ethereum Foundation published a GitHub repository that documents the eight affected invariants. It includes explanations, examples and steps developers can use to check their own code. Fixed gas budgets and gas reserves are the most common issues found so far.
Other risks include contracts that assume gas use only moves in one direction. Some assume fixed gas allowances will stay enough. Others assume a reverted call cannot return gas already spent on creating state.
Hoodi Fork on Hold
The Hoodi activation was first set for Oct. 26 at 17:42:48 UTC. The earlier postponement removed the Amsterdam execution-layer and Gloas consensus-layer activations from the schedule. It also removed a planned rise in the testnet gas limit to 200 million.
No replacement date has been announced. The Hoodi fork will not go ahead until the issues are resolved, the Foundation said. Developers are checking whether affected contracts can be updated on their own or whether the upgrade specifications must change.
Ethereum Foundation developer Marius van der Wijden said the group is working with ChainSecurity and Dedaub. It is also running internal audits to assess the effects on existing applications. The Foundation said its reviews cannot cover every project, especially where contracts interact with off-chain systems.
It has asked developers and independent auditors to review both on-chain contracts and off-chain tools. These include wallets, relayers and other infrastructure that may use hardcoded gas limits. Findings should be sent before the next All Core Developers discussions.
Reports should list the affected contract, the invariant involved, possible fixes and tests where available. They can be sent privately to glamsterdam@ethereum.org. Based on the feedback, developers may adjust EIP-8037 and EIP-8038.
Glamsterdam went live on the Sepolia testnet on Oct. 6. Developers there began testing its scaling changes under a 200 million gas limit. The upgrade also adds enshrined proposer-builder separation through EIP-7732 and block-level access lists through EIP-7928.
In an August assessment, the Foundation said replays of past transactions showed most smart contracts were unaffected by the pricing changes. A smaller group needed higher gas limits or larger changes to avoid unexpected failures.
On Oct. 26, developers also merged a validator deposit fix. It addressed a flaw that could have credited staking deposits to block builders sharing the same public key. Regression tests were added to the specifications.
The Foundation said work on the next upgrade, Hegota, continues in parallel and is not affected by the Glamsterdam delay.
