The planned activation of Ethereum's Glamsterdam upgrade on the Hoodi test network has been pushed back, security firm ChainSecurity said Thursday, after the auditor uncovered problems tied to how the upgrade changes gas. The activation had been scheduled for October 26, 2026.

The delay matters because ChainSecurity identified 13 real-world examples of deployed contracts that could permanently record a failed operation their code was designed to keep retryable. The finding puts Ethereum's tentative path toward a year-end mainnet deployment in question while developers investigate how the upgrade's proposals interact with existing smart contracts.

Why the Glamsterdam Upgrade Was Delayed

According to the auditor's analysis, the upgrade's revised gas rules undermine the assumptions many contracts rely on when an external call does not succeed. Certain contracts verify how much gas remains, or count on a call running dry, as protection against a tactic known as insufficient gas griefing, in which an attacker deliberately supplies too little gas so a valid operation fails and is recorded as a permanent failure.

The firm found that once the new rules apply, a failed call may see its gas refilled or handed back, and repricing can alter how much gas that call requires. The firm warned on October 13, 2026, that the two proposals behind the changes could weaken those safeguards.

"Even with unchanged contract code, a failure path that previously reverted can now complete," ChainSecurity wrote. The firm urged projects to review their contracts.

Two proposals sit at the center of the issue: EIP-8037 and EIP-8038 rework what the network charges to create and access stored data, and they carve out a separate pool of gas dedicated to creating new state. ForkLog reported that creating a new storage cell with an empty reserve would require 110,020 gas units instead of the previous 22,100 under the revised rules.

13 Contracts Identified, Disclosure Under Way

"It has just been decided to delay the Glamsterdam hard fork on the Hoodi testnet because of security impacts we identified," ChainSecurity wrote, adding that it had "already found 13 real-world examples" and was in responsible disclosure with the affected projects.

The auditing firm has begun reaching out to the affected projects through responsible disclosure, and the Ethereum Foundation is working to determine how many contracts in total are exposed. Researchers have not publicly identified the 13 affected contracts while that process continues, according to Bitcoin News.

According to the Ethereum Foundation, holding back the activation gives developers room to examine how the upgrade's proposals behave against smart contracts already in use. In mid-October, the foundation had called on developers to audit contracts built around fixed gas limits and expectations about how much gas remains once a call ends, ForkLog reported.

What Hoodi Node Operators Must Do

Hoodi node operators should use software that removes the scheduled upgrade. Ethereum researcher Christine Kim recommended that operators either downgrade to a previous release in which the fork is not scheduled, or hold off until their execution client team publishes a version that cancels it.

A release stripping Glamsterdam from Hoodi's schedule would arrive that same day, according to Preston Van Loon, who works on the Prysm consensus client. Along with the delay, the planned increase of the gas limit per block on Hoodi to 200 million was canceled.

The move withdraws only the settings for upcoming upgrades and leaves Hoodi's existing on-chain history untouched, according to KuCoin's report of the Ethereum Foundation announcement. The foundation emphasized that the delay does not require any action from mainnet users and ETH holders, ForkLog reported.

Glamsterdam's Features and Sepolia Activation

The upgrade is already running on Sepolia, a separate Ethereum test network that switched it on October 6. Since then, Sepolia has been producing blocks with a gas limit of nearly 200 million, more than three times mainnet's roughly 60 million.

Among its other changes, Glamsterdam introduces block-level access lists so computers can verify transactions in parallel, and it brings the auction that determines who assembles each block into Ethereum's own rules. ForkLog described these as the separation of block proposal and building functions, known as ePBS, alongside block-level access lists and a revision of the costs of certain operations.

Hoodi is essential for testing whether the Glamsterdam upgrade functions as intended before it is deployed on the main network, according to TronWeekly. Developers had considered an early December mainnet window and planned to finalize the schedule after successful Hoodi testing.

What Comes Next for the Glamsterdam Upgrade

Before the delay, developers had been aiming to ship Glamsterdam on mainnet by the end of 2026. It would come ahead of Hegotá, the following upgrade, which is expected in 2027 and could add native privacy features, Decrypt reported. No new date has been set for the Hoodi fork.

According to TronWeekly, the next steps for Glamsterdam are researching the identified threats, deciding whether any modifications are needed, and publishing a new date for the Hoodi tests. Developers need to determine whether changes should be made to EIP-8037 before the next test process starts.

The Ethereum Foundation has not announced a replacement testing date or confirmed a mainnet launch, according to Bitcoin News. KuCoin reported that the foundation's announcement described the postponement as a way to further investigate interaction effects between EIP-8037 and mainnet smart contracts.

Conclusion

Ethereum's Glamsterdam upgrade is off the Hoodi testnet schedule after ChainSecurity identified 13 deployed contracts that could permanently record failures meant to stay retryable under the new gas rules. The Ethereum Foundation says the pause gives developers time to study how the proposals interact with existing contracts, and no mainnet user action is required. The next concrete step is the completion of that investigation, a decision on whether EIP-8037 needs changes, and the publication of a new Hoodi testing date, which developers have not yet set.

Frequently Asked Questions

Why was the Ethereum Glamsterdam upgrade delayed on the Hoodi testnet?

Developers postponed the October 26, 2026 activation after ChainSecurity found that Glamsterdam's gas changes could undermine the assumptions contracts rely on when an external call fails. The auditor uncovered 13 real-world examples of contracts that could permanently record a failed operation their code was designed to keep retryable.

How many contracts did ChainSecurity find at risk from Glamsterdam?

ChainSecurity found 13 real-world examples of potentially affected contracts. The firm is contacting those projects through responsible disclosure while the Ethereum Foundation assesses how many contracts in total are exposed. Researchers have not publicly named the 13 contracts while disclosure continues.

What should Hoodi node operators do after the Glamsterdam delay?

Hoodi node operators should run software that removes the scheduled upgrade. Ethereum researcher Christine Kim advised operators to revert to an older release that does not schedule the fork, or hold off until their execution client team publishes a version that cancels it. Prysm developer Preston Van Loon said such a release would be issued the same day.

Do ETH holders or mainnet users need to take any action?

No. The Ethereum Foundation emphasized that the delay does not require any action from mainnet users and ETH holders, according to ForkLog. The postponement affects only the Hoodi testnet configuration and does not roll back any on-chain history.

When will Glamsterdam launch on Ethereum mainnet?

No date is confirmed. Developers had targeted mainnet deployment by the end of 2026 and had considered an early December window, but no new Hoodi testing date has been set. The Ethereum Foundation has not announced a replacement testing date or confirmed a mainnet launch.