Ethereum’s Glamsterdam Test Hits the Brakes After Security Findings

By Isaac • October 22, 2026 11:07 pm •

Ethereum’s next major upgrade just hit the kind of speed bump that matters.

Developers have pulled the planned Glamsterdam activation from the Hoodi testnet after security researchers identified gas-accounting changes that could make existing smart contracts behave differently—even when their code has not changed.

That does not mean Ethereum is broken. It means the final public rehearsal for a major protocol change is no longer happening on the timetable developers had been working toward.

CryptoSlate reported that the October 26 Hoodi activation was halted after ChainSecurity identified 13 real-world examples affected by the proposed changes. The firm said it is working through responsible disclosure with the projects involved.

The planned Hoodi fork was the final major