Ethereum core developers revealed a security vulnerability during the Dencun upgrade, which has now been resolved

Ethereum core developers have disclosed a security vulnerability that existed during the transition from the Ethereum mainnet merger to the recent Dencun hard fork. This vulnerability could be exploited to carry out denial-of-service attacks. The reason for this vulnerability was different RPC communication message size limits established after the merger. This flaw allows certain clients to create blocks exceeding the RPC size limit, which are still valid for other clients, thereby disrupting consensus. It could potentially lead to chain splits and potential reward losses for block proposers. Developers resolved this issue by standardizing and increasing the RPC message size limit across all clients.