Ethereum’s Glamsterdam Upgrade Stalls Over Gas Changes That Could Break Existing Smart Contracts

Ethereum’s upcoming Glamsterdam upgrade is facing another delay as developers investigate security concerns involving changes to the network’s gas-fee system. The Ethereum Foundation (EF) has recommended holding off on major decisions until independent auditors publish their findings about the potential impact on existing smart contracts.

The concerns center on two proposed Ethereum Improvement Proposals, EIP-8037 and EIP-8038. These changes are designed to adjust how the blockchain charges for creating and accessing stored data. However, security researchers have identified scenarios in which the new rules could interfere with contracts already deployed on Ethereum.

In a November 9 update, Ethereum Foundation developer Marius van der Wijden revealed that the foundation had received four reports identifying deployed contracts that could break under the proposed changes.

The reports are currently being investigated, and the foundation is contacting potentially affected development teams. The situation has prompted calls for a more cautious approach before Glamsterdam advances to its next testing stage.

Why Ethereum’s Glamsterdam Upgrade Is Facing Delays

Glamsterdam is intended to improve Ethereum's long-term scalability by changing how the network processes transactions, manages data and handles block production.

However, EIP-8037 and EIP-8038 introduce changes to gas accounting that could affect how existing smart contracts behave. Gas is the unit Ethereum uses to measure and charge for the computational work required to execute transactions and smart contracts.

The problem is that many applications were developed using the network's existing gas-cost rules. Some contracts rely on specific assumptions about how much gas remains available when an operation fails or when another contract is called.

If those assumptions no longer hold after the upgrade, certain operations could behave differently. Contracts might complete actions that previously would have failed, or otherwise valid operations could run out of gas unexpectedly.

This is particularly concerning for applications that cannot easily be updated after deployment.

Four Deployed Contracts Have Been Reported as Potentially Affected

The Ethereum Foundation confirmed that it had received four reports describing deployed contracts that could be affected by the proposed gas changes.

The foundation is reviewing the findings and contacting teams responsible for potentially vulnerable projects. It has also asked contract developers and auditors to examine eight specific invariants that could be affected by Glamsterdam.

These invariants describe assumptions that smart contracts may rely on when executing operations under Ethereum's current rules.

The reports do not mean that four contracts have already been exploited. Rather, they identify potential compatibility problems that could emerge if Glamsterdam launches with its existing specifications.

Ethlabs, which has been monitoring the reports, said none of the identified issues were currently exploitable. The concerns apply to the proposed upgrade rules and need to be addressed before they are introduced to the live network.

Independent Security Audits Will Help Determine the Next Step

The Ethereum Foundation has brought in two security auditing companies, ChainSecurity and Dedaub, to examine the proposed gas changes.

Their findings are expected to help developers determine whether the current specifications can move forward or require modifications.

According to the foundation's published schedule, the audit engagements are expected to conclude on November 13, with findings presented during a November 16 developer call. Developers are then expected to discuss the results and possible changes during a November 19 execution-layer meeting.

The foundation has recommended that All Core Devs (ACD) avoid making decisions about specification changes or a new Hoodi testnet activation date until the findings are publicly available and developers have had enough time to review them.

Several possible revisions are already being prototyped.

If the audits identify problems affecting too many deployed contracts, developers could modify the proposed gas rules or reconsider the scope of Glamsterdam.

The Planned 200 Million Gas Limit Is Also on Hold

One of Glamsterdam's major goals is to increase Ethereum's transaction-processing capacity.

The upgrade has been designed around a potential gas limit of 200 million per block, more than three times the previous 60 million target.

A higher block gas limit could allow Ethereum to process more computational work in each block, creating additional room for transactions and applications. However, increasing the limit also places greater demands on the computers operating the network.

Glamsterdam already completed an activation on the Sepolia testnet on October 6. Its next major public testing milestone was supposed to take place on the Hoodi testnet in late October.

That activation was postponed after ChainSecurity identified potential problems involving the interaction between the new gas rules and existing smart contracts.

The postponement also put the planned Hoodi gas-limit increase on hold. No replacement activation date has been confirmed. <Cite refs={["turn281123search2","turn281123search3","turn281123search6"]}/>

Developers Are Considering Different Solutions

The concerns surrounding Glamsterdam have also encouraged developers to explore alternative approaches.

Two draft proposals have emerged as possible ways to protect existing applications while allowing Ethereum to introduce its new gas-pricing system.

One approach would preserve the current gas schedule for contracts already deployed on the network while applying the revised rules to newly created contracts.

Another proposal would use separate gas accounting systems, allowing older contracts to continue operating under their existing assumptions while the network applies the new pricing rules.

Both approaches remain drafts and require further technical review. Neither has an announced implementation date.

The proposals demonstrate that developers are exploring ways to balance Ethereum's long-term scalability goals with the need to maintain compatibility with applications already running on the blockchain.

What the Delay Means for Ethereum Users and ETH Holders

For ordinary Ethereum users and ETH holders, the current delay does not require any immediate action.

The concerns relate to the proposed behavior of smart contracts after a future network upgrade. They do not indicate that users' existing ETH balances have been affected or that the network is currently experiencing an exploit involving these proposed changes.

Ethereum's mainnet activation date for Glamsterdam has not been confirmed. Developers must first determine whether the proposed gas changes can be safely introduced or need further revisions.

The upgrade remains an important part of Ethereum's scaling roadmap, but its progress now depends on resolving compatibility concerns and completing the necessary security reviews.

The decision reflects a central challenge for blockchain development: improving network performance without disrupting applications and financial systems that already depend on the existing protocol.