Glamsterdam Upgrade Brings Security Risks to Ethereum's Doorstep

Ethereum's upcoming Glamsterdam upgrade is set to launch on the Sepolia testnet on October 6, 2026. The update introduces Enshrined Proposer-Builder Separation (ePBS), which aims to increase block capacity and transaction processing time.

However, developers have raised concerns about potential security risks associated with fake builder accounts that could disrupt block building by winning bids but withholding transaction data, potentially leading to testnet paralysis.

The mainnet launch is targeted for Q4 2026, although this remains unconfirmed.