Ethereum Glamsterdam Sepolia fork stories

Oct 23, 2026

Ethereum delays Glamsterdam upgrade after security researchers flag gas-related risks

Ethereum developers postponed the Glamsterdam hard fork on the Hoodi testnet after security firm ChainSecurity identified gas-related vulnerabilities affecting existing smart contracts. The researchers flagged 13 deployed mainnet contracts where proposed gas accounting changes could convert temporary transaction failures into permanent losses.

Oct 23, 20269 sources

Sep 18, 2026

Ethereum confirms October 6 Glamsterdam testnet launch amid security warnings

Ethereum developers confirmed the Glamsterdam upgrade will activate on the Sepolia testnet on October 6, but warned that cheap test ether could allow malicious builders to exploit block auctions and potentially stall the chain during testing.

Sep 18, 20263 sources