Glamsterdam Upgrade Faces Potential Attack Risk in Oct 6 Test
Ethereum's upcoming Glamsterdam upgrade is set to undergo its first public test on the Sepolia testnet on October 6, 2026. The developers have warned that a potential attack could disrupt the test due to a weakness in the system where attackers can create fake 'builder' identities using free test ether.
During an auction process, these fake builders can submit high bids and win block auctions, but then refuse to hand over transaction data. This would not put real funds at risk but could freeze traffic on the testnet and hinder developers from evaluating the upgrade's performance under real conditions.
The existing safeguards may not be strong enough, as some client protections only kick in after several payloads go missing, and there is no way to ban individual builders.