Ethereum’s delay of the Glamsterdam upgrade on its Hoodi testnet follows a finding that some smart contracts could permanently record operations that were meant to remain retryable. Security firm ChainSecurity said Thursday that developers had postponed the activation scheduled for October 26, 2026, after it identified problems with the upgrade’s gas changes.
Key takeaways
- ChainSecurity found 13 real-world examples of potentially affected contracts.
- Hoodi node operators should use software that removes the scheduled upgrade.
- Glamsterdam is already active on Sepolia, with a gas limit near 200 million.
Ethereum’s Glamsterdam delay changes Hoodi’s upgrade plans
The Ethereum Foundation said the postponement gives developers time to investigate how Glamsterdam’s proposals interact with existing smart contracts. ChainSecurity is contacting affected projects through responsible disclosure, while the Foundation assesses how many contracts are exposed.
Ethereum researcher Christine Kim advised node operators to return to an older software release that does not schedule the upgrade, or to wait for their execution client team to issue a version that cancels it.
According to Preston Van Loon, a developer on the Prysm consensus client, a release removing Glamsterdam from Hoodi’s schedule would be issued that very day.
Gas changes can turn retryable failures into permanent records
ChainSecurity found that Glamsterdam’s gas rules could break assumptions contracts use to handle failed external calls. The firm identified 13 real-world examples in which the changes could let contracts permanently record a failed operation that their code was intended to keep retryable.
Gas pays for computing work on Ethereum. Through EIP-8037 and EIP-8038, Glamsterdam changes charges for creating and accessing stored data and adds a separate gas pool for creating new state.
Some contracts check available gas, or depend on a call exhausting its gas, to defend against insufficient gas griefing. In that attack, someone deliberately supplies too little gas, causing a valid operation to fail and be recorded as a permanent failure.
ChainSecurity warned on October 13, 2026, that the two proposals could weaken those safeguards. Under Glamsterdam, gas can be replenished or returned after a failed call, while repricing changes the amount a call needs.
“Even with unchanged contract code, a failure path that previously reverted can now complete,” ChainSecurity wrote. The firm urged projects to review their contracts.
Sepolia is live as mainnet planning awaits Hoodi testing
Glamsterdam activated on the Sepolia testnet on October 6, 2026, where blocks began using a gas limit of nearly 200 million. That is more than three times Ethereum mainnet’s 60 million limit.
The upgrade also introduces block-level access lists, which allow computers to check transactions in parallel. It brings the auction that determines who assembles each block into Ethereum’s own rules.
Before Ethereum’s Glamsterdam delay on Hoodi, developers had targeted mainnet deployment by the end of 2026. They had considered early December and planned to finalize the schedule after successful Hoodi testing.
Article produced with the assistance of artificial intelligence and reviewed by the editorial team.