Ethereum developers have postponed the planned Glamsterdam upgrade on the Hoodi test network after security researchers identified potential problems with how existing smart contracts could behave under proposed gas accounting rules. The findings raised concerns that some failed operations could be handled differently after the upgrade, prompting developers to pause the scheduled test activation.
The upgrade had been scheduled for October 26 at 17:42:48 UTC. Developers decided to postpone it during Thursday’s All Core Devs Execution meeting while they investigate the interaction between the proposed changes and contracts already deployed on Ethereum. No replacement activation date has been announced.
The issue centers on EIP-8037, a proposal to change the way Ethereum charges for creating new records in its database. The change is intended to help manage database growth as the network works toward supporting more transaction activity. However, researchers have identified potential consequences when the new rules interact with EIP-8038 and the gas limits used by existing contracts.
Why Ethereum Developers Postponed the Hoodi Test
The security concern involves how smart contracts respond when an operation they initiate fails because it runs out of gas. Gas is the resource used to pay for computation and other operations on Ethereum. Contracts can be written to catch certain failures and continue executing, record an unsuccessful attempt, disable future attempts, or move to another step.
Under some existing contract designs, developers rely on the gas remaining after a failed operation being insufficient to complete additional failure-handling steps. That can cause the overall transaction to revert, undoing its state changes. The proposed Glamsterdam changes could alter that calculation, potentially allowing some operations to complete when they previously would have reverted.
The findings were described in an October 13 analysis by ChainSecurity. The analysis examined how EIP-8037, together with EIP-8038, could affect gas consumption and the behavior of contracts that handle failed calls. The concern is about the effects of proposed rules, not evidence that Ethereum contracts are currently being exploited through these changes.
How the Proposed Gas Rules Could Affect Smart Contracts
EIP-8037 changes gas accounting for certain database operations, including the creation of new records. Under the proposed rules, gas associated with creating certain records can be restored when the corresponding changes are undone. That can leave a contract with a different amount of gas available for subsequent operations than it would have under the previous rules.
This matters because smart contracts often use gas limits as part of their execution logic, even when those limits are not intended to serve as explicit security controls. If a contract expects a failed operation to leave too little gas for its error-handling code, a change in gas accounting could allow that code to run instead. Depending on the contract’s design, this could produce a different outcome from the one its developers anticipated.
ChainSecurity also identified a potential problem in the opposite direction: certain operations could become more expensive and fail when they previously succeeded. Its analysis calculated that creating a new storage slot could require 110,020 gas when a separate allowance is exhausted, compared with 22,100 gas under the old rules. This could cause a contract to run out of gas during an otherwise valid operation.
The practical impact would depend on the contract’s implementation and how it interacts with the revised rules. The analysis demonstrates potential mechanisms for unexpected behavior, but it does not publicly establish that a major production protocol is exploitable.
What Glamsterdam Is Intended to Change
Glamsterdam is an upcoming Ethereum upgrade that includes several changes to the network. Among them are a new system for selecting block builders and improvements intended to support larger blocks. These changes are part of ongoing work to improve Ethereum’s capacity and how the network processes transactions.
The gas accounting proposals are another part of the upgrade’s technical changes. Although the aim is to manage database growth and support network improvements, the security findings show why changes to fundamental execution rules must be assessed against existing smart contracts, not just new applications.
Ethereum’s developers can use public test networks to identify these types of compatibility problems before changes reach the mainnet. The official Ethereum documentation provides background on how the network and its smart contracts work, while the Ethereum Improvement Proposals repository tracks proposals and technical discussions.
Sepolia Has Completed Its Test, but Hoodi Is Delayed
Glamsterdam completed its Sepolia testnet activation on October 6. Hoodi was scheduled to provide another public rehearsal before any potential mainnet deployment. The Hoodi test also included a planned increase in its gas limit to 200 million, which has been postponed alongside the upgrade activation.
The delay means developers have more time to review the reported edge cases, assess their security implications, and determine whether changes to the proposals or implementation are necessary. No revised Hoodi date has been confirmed, and Ethereum’s mainnet activation date for Glamsterdam remains unannounced.
The findings do not indicate that existing Ethereum contracts are currently being exploited through the proposed changes. Instead, they highlight a potential risk that needs to be understood before the new rules are activated in a public test or deployed to the main network.
