Ethereum Developers Patch Glamsterdam Validator Deposit Flaw Before Hoodi Retest

October 28, 2026 MM Crypto Team

Ethereum developers have moved quickly to fix a flaw in the code for the network’s next major upgrade, after a security review raised concerns that could have put validator deposits at risk. The episode is a reminder of how carefully Ethereum’s upgrade process is designed to work, and why a delay at the testnet stage is often a sign that the safety checks are doing their job rather than a sign that something has gone wrong with the upgrade itself.

The upgrade in question is Glamsterdam, the next major upgrade for Ethereum after Fusaka. Its testnet activation had originally been scheduled for October 26 at 17:42:48 UTC, but that date was postponed after ChainSecurity flagged gas-accounting risks in EIP-8037 and EIP-8038. Developers then merged a fix on October 26 for a deposit flaw that could have let operators withdraw ETH meant for new validators. The flaw could have misdirected validator deposits to block builders, and no losses were recorded. Client teams must now implement the fix before mainnet, and the testnet will need to be retested before the upgrade can move forward.

What Glamsterdam Is Trying To Change

Glamsterdam is Ethereum’s next major upgrade after Fusaka, and like every upgrade in the network’s history it is a package of changes rather than a single feature. Each upgrade bundles together a set of Ethereum Improvement Proposals, known as EIPs, that have been discussed, debated and refined by developers, researchers and client teams over many months. Some of those proposals change how the network processes transactions, some change how fees are calculated, and some change how validators and other participants interact with the protocol.

The two proposals at the centre of this delay, EIP-8037 and EIP-8038, were flagged by ChainSecurity for gas-accounting risks. Gas is the name Ethereum gives to the fee system that measures how much computational work every transaction and every operation on the network requires. Getting gas accounting right matters enormously, because if the network charges too little for an expensive operation, it can be abused, and if it charges too much, ordinary users end up paying more than they should. A flaw in gas accounting can also create unexpected behaviour in parts of the system that depend on those calculations being correct, which is why a warning from a security firm is taken seriously even when the problem sounds technical and narrow.

The deposit flaw that developers fixed on October 26 is a separate but related part of the same story. Validator deposits are the mechanism by which new validators join the network. An operator sends ETH as a deposit, and that deposit is meant to be held for the new validator so that the validator can take part in securing the network and earning rewards for doing so. If that deposit could be misdirected, the consequences would be serious, because the ETH would not end up where it was supposed to go. In this case, the flaw could have let operators withdraw ETH meant for new validators, and the deposits could have been misdirected to block builders instead. Block builders are the participants who assemble transactions into blocks, and they play an important but very different role from validators. Money meant for one role ending up with another would have undermined trust in the deposit process itself.

That no losses were recorded is an important detail. The flaw was found during testing, before it could affect real deposits on the main network. That is the whole point of running upgrades on testnets first. A testnet is a live copy of the network where developers can try out new code in realistic conditions without putting real funds at risk. When a testnet activation is postponed, it can look like a setback from the outside, but for the people building the network it is a normal and healthy part of the process. A problem found on a testnet is a problem that will not reach users.

How Validator Deposits Work And Why They Matter

To understand why a deposit flaw matters so much, it helps to understand what validators do and why deposits are the gateway to becoming one. Ethereum is secured by validators, participants who lock up ETH and take on the responsibility of checking transactions, proposing blocks and keeping the network honest. In return for doing that work correctly, they earn rewards. If they behave dishonestly or fail to do their job, they can be penalised. The deposit is what makes that system work, because it gives every validator something at stake.

The deposit process has to be precise. The ETH sent by an operator must be recorded correctly, attributed to the right validator, and held in the right place until the validator is ready to start work. If any part of that chain goes wrong, the validator may not be able to start, the operator may lose funds, or the network may end up with a record that does not match reality. That is why developers treat deposit code with particular care, and why a flaw in that code is treated as a high-priority fix even when it is found early.

The possible misdirection to block builders adds another layer to the story. Block builders and validators work together to keep Ethereum running, but they have different incentives and different roles. A builder assembles the contents of a block, while a validator proposes and attests to blocks. If funds meant for validators could flow to builders, the separation between those roles would blur in a way that the protocol never intended. The fix merged on October 26 closes that path, and client teams must now implement it so that every version of the software carries the correction.

Why Testnet Activations Are Delayed When Audit Issues Surface

Testnets exist to catch exactly this kind of problem, and delays are a feature of the system rather than a failure of it. When an upgrade is scheduled for a testnet, developers, client teams, researchers and security firms all watch how the new code behaves. They run their own tests, they try to break things, and they compare what the code does with what it was supposed to do. If someone finds a problem, the honest and responsible response is to stop, fix the problem, and test again.

That is what happened with Glamsterdam. ChainSecurity flagged gas-accounting risks in EIP-8037 and EIP-8038, and the testnet activation that had been scheduled for October 26 at 17:42:48 UTC was postponed. The postponement gave developers time to work on the fix without the pressure of a live testnet running code they already knew needed to change. It also gave client teams time to understand the problem and prepare their own updates.

This kind of pause is common in Ethereum’s history. Major upgrades have been delayed before when testing revealed problems, and in almost every case the delay made the final upgrade safer. The alternative would be far worse. Pushing ahead with code that is known to have a flaw, in the hope that the flaw will not matter in practice, would put real users and real funds at risk. Ethereum’s developers have consistently chosen the slower and safer path, and the network’s long record of stability is one of the reasons that approach is trusted.

What The Delay Means For The Upgrade Timeline

A delay at the testnet stage naturally raises questions about the timeline for the upgrade as a whole. Will Glamsterdam reach the main network later than planned, and does the delay tell us anything about the health of the upgrade? The honest answer is that a testnet delay does not automatically mean a long delay for mainnet, but it does mean that the schedule will depend on how quickly the fix is implemented and how cleanly the retest goes.

The next step is a retest on Hoodi, the testnet where the activation was originally planned. Hoodi is one of the public testnets that Ethereum uses to trial upgrades before they go live. A successful activation on Hoodi, with the fixed code in place, would be a strong signal that the upgrade is ready to move to the next stage. If the retest reveals further problems, those will need to be fixed too, and the timeline will move again. That is how the process is supposed to work, even if it can be frustrating for people waiting for new features.

For users, the practical effect of the delay is limited in the short term. Glamsterdam is a major upgrade, but Ethereum will continue to work exactly as it does today while the upgrade is being tested. Transactions will still be processed, validators will still secure the network, and applications built on Ethereum will still run. The upgrade is about improving the network for the future, not about fixing something that is broken today, so a careful delay is far better than a rushed launch.

Frequently Asked Questions

What is the Ethereum Glamsterdam upgrade?

Glamsterdam is Ethereum’s next major upgrade after Fusaka. It bundles together a set of proposals that change how the network works, and it must be tested on public testnets before it can be activated on the main network.

Why was the Glamsterdam testnet activation postponed?

The activation, originally scheduled for October 26 at 17:42:48 UTC, was postponed after ChainSecurity flagged gas-accounting risks in EIP-8037 and EIP-8038. Developers also merged a fix on October 26 for a deposit flaw that could have misdirected validator deposits.

Could the deposit flaw have caused losses?

No losses were recorded. The flaw was found during testing, before it could affect real deposits on the main network, and the fix was merged before the upgrade moved forward.

What happens next for Glamsterdam?

Client teams must implement the fix in their software, and the upgrade will be retested on the Hoodi testnet. A successful retest would be a strong step toward a mainnet activation.

Source: CoinStats

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