MEV Bot Beats Hacker to $7.8M Ethereum Exploit, But Whale's Assets Still Aren't Safe

A blockchain security incident on Ethereum saw an automated trading program called Yoink intercept an attempted $7.8 million theft of rsETH tokens before the original attacker could complete it. The hacker had targeted a customised module linked to a Safe smart contract wallet, using a publicly accessible function to redirect assets through a manipulated Uniswap v4 pool and convert them into a liquid restaking token.

According to blockchain security firm Blockaid, the Yoink bot detected the exploit attempt as it unfolded and executed its own transaction first, securing the tokens before the hacker's transaction could go through. Yoink then split the proceeds across wallets and paid a large fee to a block builder to guarantee its transaction was processed ahead of the attacker's. The hacker's original transaction ultimately failed.

While the outcome meant the funds did not end up with the criminal, they also did not return to the original wallet owner, since Yoink is an automated profit-seeking bot rather than a security tool. This case highlights how vulnerabilities in custom smart contract modules and wallet integrations can be exploited quickly, and how the same automated systems that scan for such flaws can sometimes act faster than either attackers or defenders.