Ethereum's Pectra upgrade faces issues on Sepolia testnet

The recent Pectra upgrade on Ethereum's (CRYPTO:ETH) Sepolia testnet encountered significant problems, exacerbated by an unknown attacker exploiting an edge case.

Launched on March 5, the upgrade aimed to improve Ethereum's functionality but quickly ran into errors, including the mining of empty blocks.

Developer Marius van der Wijden reported that the issues arose when the deposit contract triggered incorrect events, leading to operational failures.

Despite an initial fix being deployed, the situation worsened when an attacker sent zero-token transfers to the deposit address, causing further disruptions.

Van der Wijden noted that this exploit led to a recurrence of empty blocks being mined, prompting a deeper investigation into the transaction pools.

Initially suspected to be a mistake from trusted validators, it was later revealed that the problematic transactions originated from a newly funded account.

The ERC-20 standard allows for zero-token transfers, which the attacker utilised to disrupt the network.

To mitigate the issue, developers implemented a private fix on select nodes without publicising it due to concerns that the attacker might be monitoring their communications.

By 2 PM on March 5, all nodes were updated with this fix, allowing normal operations to resume.

Importantly, despite these setbacks, finalisation was not lost during the incident, and the problems were confined to the Sepolia testnet due to its use of a token-gated deposit contract.

Prior to this incident, the Pectra upgrade had already faced challenges during testing on the Holesky testnet.

As a result of these ongoing issues, developers have decided to postpone the mainnet launch of Pectra until further testing can ensure stability and security.

The upgrade is significant as it follows Ethereum's Dencun upgrade and is designed to enhance staking and scalability across layer-2 networks.

At the time of reporting, the Ethereum (ETH) price was $2,065.48.