ChainSecurity disclosed on October 22, 2026, that it had identified 13 real-world deployed mainnet contracts vulnerable to gas-accounting changes under Glamsterdam.

From the articleEthereum Delays Glamsterdam Upgrade After Security Researchers Flag RisksAlso in Ethereum Delays Oct 26 Glamsterdam Hoodi Upgrade Over Security Risks, Ethereum Glamsterdam Delay: ChainSecurity Flags 13 Contracts Where Failures Turn Permanent, Ethereum Delays Glamsterdam Testing After 13 Contracts Trigger Concerns, Ethereum Delays Glamsterdam Testnet Fork Over Gas Security Flaws - Decrypt, Ethereum's long-awaited Glamsterdam upgrade hits another roadblock as 13 security risks emerge