Ethereum delays Glamsterdam Hoodi testnet launch over security risks

Ethereum postponed Glamsterdam’s planned Hoodi testnet deployment, originally scheduled for Oct. 26. The delay concerns the entire hard-fork testnet launch, not a single contract or tool. Developers need more time to examine how Glamsterdam’s gas proposals interact with smart contracts already deployed on Ethereum.

The immediate trigger was a warning from ChainSecurity about EIP-8037 and EIP-8038. Under the proposed rules, gas could return to a contract after an operation fails. That change may weaken safeguards against insufficient gas griefing, where a caller supplies too little gas and causes an operation to fail.

The Ethereum Foundation said the launch would be delayed while developers investigate. ChainSecurity later reported 13 real-world examples and began responsible disclosure with affected projects. The postponement creates uncertainty around Glamsterdam’s mainnet timing, which developers had been considering for early December.

ChainSecurity identified 13 real-world examples of smart contracts potentially affected by Glamsterdam’s proposed gas changes. This number refers to concrete cases found during the security firm’s analysis, rather than a prediction that every Ethereum contract will fail. The finding helped prompt the postponement of Glamsterdam’s Hoodi testnet launch.

The risk involves contracts that use remaining gas as part of their security logic. If an operation fails but gas is returned to the contract, the contract may continue running in a situation where it previously would have stopped. That behavior could interfere with checks designed to detect insufficient gas griefing.

ChainSecurity did not disclose the examples’ details or identify the affected projects. It said it was coordinating responsible disclosure and urged developers to check their contracts as soon as possible. The 13 examples therefore signal a review need, not a public list of confirmed exploits.

Glamsterdam is a planned Ethereum hard fork, meaning a coordinated protocol upgrade that changes the rules governing how the network processes activity. The upgrade includes gas-related proposals, especially EIP-8037 and EIP-8038. It matters because smart contracts, wallets, indexers, and other tools often depend on those rules behaving consistently.

A hard fork can change rules by introducing new software logic for processing transactions and contract operations. Nodes and other network participants that adopt the upgrade follow the new behavior. In Glamsterdam’s case, the proposed changes could return gas to a contract after an operation fails. That may alter what the contract can do next.

Ethereum is testing Glamsterdam on public testnets before a mainnet deployment. Sepolia activated it on Oct. 6, while Hoodi’s planned launch was postponed after security concerns. Developers had been considering early December for mainnet, but the schedule now remains uncertain.

EIP-8037 and EIP-8038 are proposals included in Glamsterdam that change how Ethereum handles gas after a failed operation. ChainSecurity warned that gas could be returned to the contract rather than remaining consumed in the same way. This matters because existing contracts may use gas behavior as a safety signal.

The key mechanism is continued execution. Under the proposed rules, a contract might receive gas back after an operation fails and then keep running. Previously, the available gas could have been low enough to stop execution. Security checks built around that earlier behavior might no longer work reliably, especially checks related to insufficient gas griefing.

ChainSecurity emphasized that not every gas-based check would become unreliable. However, developers must review their contracts against the new rules. The concerns led Ethereum developers to postpone Glamsterdam’s Hoodi testnet launch while they investigate the interaction with deployed contracts.

Insufficient gas griefing is an attack in which a malicious caller deliberately provides too little gas for a legitimate smart-contract operation to succeed. The caller may not need to steal funds directly. Instead, the goal is to trigger failure in a way that harms the contract’s normal process or the user trying to use it.

The proposed Glamsterdam gas changes could make this attack harder for existing safeguards to detect. If the operation fails but gas returns to the contract, execution may continue. A contract could then update its records, such as marking an operation as failed, removing a claim, or disabling a retry option. Checks that rely on low remaining gas may no longer behave as expected.

ChainSecurity warned that developers should review such protections under the new rules. It identified 13 real-world examples and coordinated responsible disclosure with affected projects. The Hoodi launch was postponed while Ethereum developers investigated these interactions before moving toward mainnet.

If a contract permanently records a failed operation, a user may lose access to an action that should still be available. The article gives a direct example: the contract could remove the user’s claim or disable the option to retry it. The user would then be unable to complete an otherwise valid operation.

The danger comes from how the contract interprets failure. A malicious caller can provide too little gas, causing a legitimate operation to fail. Under Glamsterdam’s proposed gas behavior, gas may return to the contract after that failure, allowing execution to continue. Existing safeguards might then incorrectly treat the failed attempt as final.

This is a potential security consequence, not a claim that every contract will behave this way. ChainSecurity said some gas-related checks could still work, but developers must review them. Its 13 real-world examples and responsible-disclosure effort prompted the Hoodi delay for further investigation.

Ethereum uses gas to measure the computational work performed by transactions and smart contracts. It helps account for network resources and prevents a transaction from running without a defined execution cost. Because contracts and tools rely on gas behavior, a protocol change can affect more than transaction fees.

Glamsterdam’s proposed changes illustrate the risk. If gas returns to a contract after an operation fails, the contract may continue running when it previously would have stopped. Existing security checks might misread the amount of gas remaining. A malicious caller could exploit that difference through insufficient gas griefing, potentially causing failed operations to be recorded permanently.

The effects can extend across the ecosystem. The Ethereum Foundation warned that wallets, indexers, and gas estimators relying on fixed assumptions could break. Developers must also inspect existing contracts. These concerns led to the Hoodi delay while Ethereum contributors assess compatibility before mainnet timing is set.