Glamsterdam Hoodi delay: Ethereum Pauses Test Over Gas Risk

The Glamsterdam Hoodi delay is official: Ethereum core developers have called off the upgrade's activation on the Hoodi testnet, which was set for 17:42:48 UTC on Monday, October 26. Security researchers found that new gas rules in the upgrade could change how existing smart contracts handle failures, and no replacement date has been set.

What actually happened

The Ethereum Foundation blog posted the notice on October 22. It removes the scheduled Amsterdam execution-layer and Gloas consensus-layer activations at epoch 132,352, plus the gas-limit schedule that would have raised Hoodi to 200M at the same time.

The EF stresses this rolls back the configuration for a future upgrade. It does not rewind Hoodi's chain history. The old activation is simply gone, with no new epoch or timestamp in the updated config.

Glamsterdam already went live on the Sepolia testnet on October 6, according to CoinDesk. Hoodi was meant to be the next public rehearsal before mainnet. The upgrade bundles a new system for choosing block builders and changes meant to let Ethereum handle larger blocks.

The bug that is not a bug yet

The problem centers on EIP-8037, which changes how Ethereum charges for creating new state, the records stored in its database. The goal is to slow state growth as Ethereum scales up the number of transactions it can process.

CoinDesk explains the risk, based on an October 13 analysis by security firm ChainSecurity. Some contracts catch a failed call and then do something, like record that an attempt failed or disable further tries. Developers sometimes rely on the leftover gas being too low for that step to finish, so the whole transaction reverts instead.

Under the proposed rules, gas spent creating certain records can be refunded when those changes are undone. That can leave enough gas for a contract to finish a failure-handling step that would have reverted before, making an error permanent.

There is a risk the other way too. ChainSecurity calculated that creating a new storage slot could cost 110,020 gas once a separate allowance runs out, versus 22,100 under the old rules. A contract with a fixed gas budget could then fail during an otherwise valid operation.

ChainSecurity showed the mechanism, not a live exploit. CoinDesk notes it has not been shown that any major production protocol is exploitable.

Why the Glamsterdam Hoodi delay matters

For users, nothing breaks today. For builders, it is a reminder that "gas repricing" sounds boring until it changes how your contract behaves. Ethereum is choosing to slow down rather than ship a rule change that might quietly alter old contracts.

That is the tradeoff every fast-moving chain faces. Base just moved to faster blocks on testnet, as we covered in our Base Denim upgrade piece, and Solana pushed finality changes in our Solana Alpenglow activation explainer. Ethereum's process is slower, and this week shows why its devs defend that.

What node operators need to do

If you run a Hoodi node or validator, update both execution and consensus clients to releases that explicitly remove the October 26 activation. The EF lists, among others, Lighthouse v8.3.2, Prysm v7.3.1, Teku 26.10.2, Nimbus v26.10.2 and Lodestar v1.50.1 on the consensus side, plus go-ethereum v1.17.10, Nethermind 2.2.1, Besu 26.10.1 and Reth v2.8.1 on the execution side. Grandine and Erigon were listed without a version number when we checked.

Do not assume the client versions in the earlier Hoodi announcement include the postponement. The EF says to follow each client team's release notes.

What to do as a reader

If you just hold ETH, the EF is clear: no action is needed for mainnet users. Ignore anyone telling you to "migrate" or "claim" anything because of the Glamsterdam Hoodi delay. That is a classic phishing hook.

If you build contracts, check any code that catches out-of-gas failures and assumes there will not be enough gas left to do something afterward. That pattern is exactly what the researchers flagged. A new Hoodi date will be announced separately, so watch the EF blog, not random screenshots.

Sources: Ethereum Foundation blog and CoinDesk.