Ethereum pauses Hoodi testnet fork after retryable failure warning

Ethereum's Hoodi testnet fork is delayed after ChainSecurity found gas changes could permanently lock retryable smart contract failures. Operators should watch for a revised schedule.

What happened

Ethereum developers have postponed the planned Glamsterdam upgrade on the Hoodi testnet after security firm ChainSecurity said the upgrade's gas changes could create a security problem. The auditor announced the delay on Thursday, and Decrypt reported the decision on Oct 23, 2026.

ChainSecurity said the changes could let some smart contracts permanently record failed operations that their code was designed to keep retryable. It added that it has already found 13 real-world examples and is contacting affected projects through responsible disclosure, while the Ethereum Foundation assesses how many contracts are exposed.

In a statement, ChainSecurity wrote:

“It has just been decided to delay the Glamsterdam hard fork on the Hoodi testnet because of security impacts we identified.”

Key facts

• The Glamsterdam hard fork on the Hoodi testnet has been delayed because of security impacts identified by ChainSecurity.
• The flagged gas changes could let some smart contracts permanently record failed operations that were designed to remain retryable.
• ChainSecurity said it has already found 13 real-world examples and is in responsible disclosure with the affected projects.
• The Ethereum Foundation is assessing how many contracts are exposed to the issue.
• The delay was announced on Thursday, according to ChainSecurity.

Our analysis

The delay matters because testnet forks are normally the last checkpoint before mainnet changes. When a security auditor halts that step, it suggests Ethereum developers are treating gas-related smart contract failures as a serious enough risk to pause the schedule rather than push forward. For operations teams, the key change is not the delay itself but the nature of the flaw: retryable operations could become permanently locked.

This is different from a routine timing slip. A hard fork that changes gas behavior can alter how contracts absorb failures, which likely affects builders who rely on retry patterns in smart contract code. The fact that ChainSecurity found 13 real-world examples suggests the issue is concrete enough to trace to live or near-live contract designs, not just a theoretical edge case.

The Ethereum Foundation's assessment of how many contracts are exposed will likely shape the next timeline. Operators should expect a revised Hoodi schedule, not assume the original Monday plan remains valid.

What it means for operators

• Watch official Ethereum Foundation and ChainSecurity channels for a revised Hoodi testnet activation date and exposure details before updating nodes or validators.
• Review smart contract logic that treats failed operations as retryable, especially where gas limits or gas behavior may affect state changes.
• Hold the previous Monday activation assumption: do not schedule maintenance or user communications around the old testnet fork timing.
• If you run community accounts or developer newsletters, flag that this is a security-driven delay, not a minor bug or routine postponement.

This article is news and operational analysis only, not investment advice.