TLDR
Ethereum developers postponed the Glamsterdam upgrade on the Hoodi testnet, which was set for October 26, 2026, and no new date has been set.
Security firm ChainSecurity warned that gas changes in EIP-8037 and EIP-8038 could weaken protections against insufficient gas griefing attacks.
ChainSecurity says it has found 13 real-world smart contracts that could be affected and is working with those projects on responsible disclosure.
Mainnet users and ETH holders do not need to take action, but node and validator operators must update their client software.
A December mainnet launch is still possible, with a revised Hoodi date expected after Devcon on November 3 to 6.
Ethereum developers have postponed the Glamsterdam upgrade on the Hoodi testnet. The upgrade was set to go live on October 26, 2026. No new date has been announced.
The decision was made during All Core Devs Execution call #248. The Ethereum Foundation said the delay gives developers time to study how some proposed changes interact with smart contracts already on Ethereum.
What the Delay Covers
The postponement removes three planned changes from the October 26 date. These are the Amsterdam execution layer activation, the Gloas consensus layer activation, and a plan to raise Hoodi’s gas limit to 200 million.
The delay does not undo Hoodi’s chain history. Mainnet users and ETH holders do not need to take any action.
Node and validator operators must update their software. Clients such as Lodestar, Besu, and Nethermind must run versions that confirm the October 26 activation has been removed.
Glamsterdam already went live on the Sepolia testnet on October 6. Sepolia is not affected by this delay.
Security Firm Raises Gas Concerns
On October 13, blockchain security firm ChainSecurity warned about two proposals in Glamsterdam, EIP-8037 and EIP-8038. The firm said these changes could weaken protections against an attack known as insufficient gas griefing.
In this type of attack, a caller gives a smart contract too little gas to finish a valid task. ChainSecurity said the new rules could let gas return to a contract after an operation fails, so it keeps running when it would have stopped before.
This could cause problems for contracts that rely on gas checks for security. For example, a contract could remove a user’s claim or block a retry, leaving the user unable to complete a valid action.
ChainSecurity said not all gas-based safety checks would fail. Some would still work, but developers would need to review them against the new rules.
On October 21, security researcher pcaversaccio called the risks “serious” in a GitHub comment. The researcher asked developers to reassess the hard fork.
The Ethereum Foundation had earlier warned that Glamsterdam’s gas model could break some wallets, indexers, and gas estimators that rely on fixed assumptions.
Glamsterdam is Ethereum’s main scaling upgrade for 2026. It includes enshrined proposer-builder separation under EIP-7732, block-level access lists under EIP-7928, and gas repricing under EIP-8037 and EIP-8038.
Developers had been looking at early December for a mainnet launch, depending on successful Hoodi testing. The fourth quarter window remains open, with a revised Hoodi date expected after Devcon, which runs November 3 to 6.
ETH’s price showed little reaction, since the issue affects only the testnet. Institutional buying has continued, with SharpLink deploying $400 million of its ETH treasury on-chain and BitMine adding 12,535 ETH.
On Friday, ChainSecurity said it had found 13 real-world examples of smart contracts that could be affected. The firm did not name the projects and said it is working with them on responsible disclosure. It urged developers to check their contracts as soon as possible.
