Ethereum Halts Glamsterdam Hoodi Fork Over Eight Smart-Contract Risks

November 7, 2026 MM Crypto Team

Ethereum developers have hit pause on the Glamsterdam upgrade’s next testnet step. The Ethereum Foundation said in a blog post on Friday, November 6, that the upgrade will not be activated on the Hoodi testnet until risks to smart contracts identified by auditing firm ChainSecurity are resolved. It is a specific, new development — not a repeat of the earlier general delay story, but a concrete halt tied to eight smart-contract invariants that the new gas rules could break.

The decision was taken by the All Core Developers group, the body that coordinates Ethereum’s upgrades, after ChainSecurity’s report landed on October 13. The Foundation has published a GitHub repository documenting all eight affected invariants, with explanations, examples, and guidance for developers to check their own code. It is also collaborating with several audit firms on further reviews and internal audits. But it has been frank about the limits of that work: it cannot check all on-chain and off-chain code for every project, so it is urging contract developers and auditors to check for themselves whether their projects rely on any of the eight invariants.

What the Ethereum Glamsterdam Hoodi Delay Means

Hoodi is a testnet, a full copy of Ethereum where upgrades are rehearsed before they reach the main network. A hard fork on Hoodi is one of the final rehearsals before a change goes live for real users and real money. Pausing it is exactly what testnets are for: finding problems safely instead of on mainnet.

This is not the first time Glamsterdam’s Hoodi activation has slipped. Developers had already postponed a planned October 26 activation last month to study EIP-8037’s effect on mainnet smart contracts, and have since merged a fix for a builder deposit flaw. The new halt extends that caution. Glamsterdam went live on the Sepolia testnet on October 6, another major rehearsal, testing under a 200 million gas limit. Sepolia gave the team useful data, but Hoodi is the dress rehearsal that matters most, and the team is not willing to run it until the invariant problem is understood.

For users, the practical impact is limited. ETH traded at $2,229 on November 6, down 1.2% over 24 hours according to CoinMarketCap, a modest move that suggests the market treated the news as a routine engineering delay rather than a crisis. No user funds are at risk, no applications have stopped working, and the main network is unaffected. The delay matters most to developers and to the timetable for the upgrade itself, not to anyone holding or using ETH today.

EIP-8037 and EIP-8038: The Gas Changes Behind the Risk

To understand the problem, it helps to understand what the two proposals do. Every action on Ethereum costs gas, a fee measured in tiny units that pays for the computing work involved. EIP-8037 adjusts the cost of creating new blockchain state — writing fresh data to the chain for the first time. EIP-8038 adjusts the fee for accessing existing state — reading data that is already stored. Both are part of Glamsterdam’s broader effort to make gas pricing reflect the real cost of execution more accurately, so that the network charges fairly for the work it performs.

The trouble is that many smart contracts were written with assumptions about how much gas certain operations cost. Developers built in expectations — sometimes explicit, sometimes buried deep in the logic — that a particular call would cost a particular amount, or that a call would succeed or fail in a particular way depending on the gas available.

ChainSecurity’s finding is that EIP-8037 and EIP-8038 could break contracts that rely on fixed gas-related assumptions when external calls fail. An external call is when one smart contract calls another — a routine event in decentralised finance, where lending protocols, exchanges, and token contracts constantly interact. If the gas cost of that call changes, the calling contract’s assumptions about what happens next may no longer hold. None of this has happened on mainnet, because the changes have not been activated there. The point of the audit is to catch the risk before it can.

Eight Smart-Contract Invariants and the ChainSecurity Audit

An invariant is a rule that a piece of software is supposed to follow always, no matter what. In smart contracts, invariants are the guarantees that users and other contracts rely on: that a balance can never go negative, that a withdrawal always returns the right amount, that a particular function always succeeds when its conditions are met. ChainSecurity found eight such invariants that the gas changes could break, and the Foundation’s GitHub repository documents each one with explanations, examples, and guidance.

The repository is an important part of the response. Rather than simply announcing a delay, the Foundation has given developers the tools to check their own code. The repository explains what each invariant is, shows examples of the kind of code that relies on it, and offers guidance on how to test whether a project is affected.

The Foundation is also working with multiple audit firms on further reviews and internal audits. But it has been candid that this work cannot cover everything. Ethereum hosts hundreds of thousands of contracts, plus off-chain systems that interact with them, and no single team can review them all. That is why the Foundation is urging developers and auditors to check their own projects against the eight invariants. The responsibility is shared, and the projects that take the warning seriously will be the ones that are ready when Glamsterdam eventually ships.

This is also a reminder of how much the audit ecosystem matters. ChainSecurity’s October 13 report is the reason the Hoodi fork is paused, and the pause is the reason a potential problem will be fixed before it reaches mainnet.

Why a Testnet Delay Is the System Working

It is tempting to read any delay as a failure, but in Ethereum’s upgrade process a testnet pause is a sign that the system is working as designed. The whole point of a staged rollout — Sepolia first, then Hoodi, then mainnet — is to catch problems at each stage and fix them before they can do harm. A delay at the Hoodi stage means the safety net caught something. The alternative would be far worse: discovering the problem after the upgrade had reached mainnet, when real funds and real applications were at stake.

Ethereum’s history supports this view. Previous upgrades have been delayed when testing uncovered issues, and the network has been more reliable for it. The culture of the core developers is deliberately cautious, and the All Core Developers group’s decision to pause Hoodi rather than push ahead fits that pattern. Nobody involved wants to be the person who approved a fork that broke contracts holding billions of dollars. A few weeks or months of delay is a small price for getting it right.

There is also a wider lesson about the complexity of changing a live system. Ethereum is not a product that can be taken offline for maintenance; it runs continuously, securing hundreds of billions of dollars in value. Changing how gas is priced touches every contract on the network, and the interactions between those contracts are too complex for any single team to fully predict. That is why the testing process is so elaborate, and why the discovery of eight affected invariants is a normal — if unwelcome — part of it.

What Happens Next for Glamsterdam and Hegota

The immediate next step is the work itself: resolving the risks ChainSecurity identified, reviewing the fixes with other audit firms, and giving developers time to check their code against the eight invariants. No new Hoodi activation date has been announced, and the Foundation has not set a public timetable for when the fork will be rescheduled. That is the right approach — a date driven by readiness rather than by a calendar — but it does mean the upgrade’s timeline is now genuinely uncertain.

Importantly, the delay does not affect Hegota, the upgrade planned for 2027, which the Foundation says is “continuing in parallel in full force.” Hegota is a separate track of work, and its progress is not held up by the Glamsterdam pause.

For the industry, the message is to take the eight invariants seriously. Developers building on Ethereum should read the Foundation’s repository, check whether their contracts rely on fixed gas assumptions, and test against the new pricing. Auditors should add the invariants to their checklists. And users should take comfort in the fact that the system caught the problem where it was supposed to be caught — on a testnet, in public, with time to fix it. Glamsterdam will arrive when it is ready, and the delay is part of how Ethereum makes sure that ready means safe.

Frequently Asked Questions

Why was the Glamsterdam upgrade paused on Hoodi?

Ethereum developers halted the Hoodi testnet activation after ChainSecurity’s October 13 report found that EIP-8037 and EIP-8038 could break smart contracts relying on fixed gas assumptions. Eight smart-contract invariants are affected.

What are EIP-8037 and EIP-8038?

EIP-8037 adjusts the cost of creating new blockchain state, and EIP-8038 adjusts the fee for accessing existing state. Both are gas pricing changes in the Glamsterdam upgrade.

What should developers do about the eight invariants?

The Foundation published a GitHub repository documenting all eight invariants with guidance, and urges developers and auditors to check whether their projects rely on any of them.

Does the delay affect the Hegota upgrade?

No. Hegota, the upgrade planned for 2027, is “continuing in parallel in full force” and is unaffected by the Glamsterdam delay.

How did ETH react to the news?

ETH traded at $2,229 on November 6, down 1.2% over 24 hours according to CoinMarketCap, a modest move suggesting the market treated the halt as a routine engineering delay.

Source: CoinDesk/CoinMarketCap

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