Ethereum developers have postponed testing of the Glamsterdam upgrade on the Hoodi testnet following security concerns discovered by Chainsecurity, a Swiss blockchain cybersecurity firm. The planned Oct. 26 activation has been canceled, and the upgrade's tentative December mainnet launch now faces uncertainty.
During the Oct. 22 All Core Developers Execution meeting, developers agreed to delay testing after reviewing findings related to two proposals, EIP-8037 and EIP-8038. Chainsecurity identified 13 deployed contracts exhibiting potentially dangerous behavior stemming from proposed changes to how the Ethereum protocol calculates gas—the fee mechanism that determines computing work capacity for transactions.
The Technical Issue
The security researchers found that certain operations under the proposed rules might unexpectedly return previously consumed gas to a transaction. This behavior creates a problem for smart contracts designed around existing spending limits. Some contracts deliberately halt operations when insufficient gas remains, allowing users to retry later. Under the new rules, a failed operation might leave enough gas for the surrounding contract to finish, potentially permanently disabling retry options or erasing users' ability to claim funds.
The affected contracts' code would not necessarily require changes for the problem to appear. Researchers have not publicly identified the 13 vulnerable contracts while responsible disclosure continues.
Impact on Glamsterdam
Glamsterdam combines improvements intended to increase Ethereum's processing capacity and make block validation more efficient. Earlier testing on the Sepolia network succeeded on Oct. 6, with blocks operating near a 200 million gas limit—more than three times Ethereum mainnet's roughly 60 million.
Hoodi testnet operators must now install updated execution and consensus software. Regular Ethereum users need take no action at this time. The Ethereum Foundation has not announced a replacement testing date or confirmed a mainnet launch window. Developers must now determine whether the proposed performance improvements can safely coexist with contracts already operating under existing rules.
