MEV Bot Yoink Intercepts $7.7M Attack, Kelp Freezes Address

A Hack Gets Hijacked

An attacker targeting a custom Safe module on Ethereum walked away with nothing after an MEV bot called “Yoink” stepped in first, capturing $7.7 million in rsETH before the exploiter could consolidate the funds – then Kelp moved to freeze the receiving address entirely.

How the Front-Run Unfolded

The original exploit was aimed at a custom Safe module, a type of smart contract extension that modifies or expands the behavior of a Gnosis Safe multisig wallet. These modules handle permissions and execution logic, and when misconfigured or vulnerable, they create narrow windows for attackers to redirect funds without triggering the usual multi-signature approvals. Someone identified one of those windows and tried to walk through it.

They didn’t make it far.

MEV – short for Maximal Extractable Value – describes the profit miners or validators can extract by reordering, inserting, or censoring transactions within a block. Bots built around MEV strategies constantly monitor Ethereum’s mempool, the waiting room for unconfirmed transactions, scanning for opportunities to front-run or sandwich trades. The “Yoink” bot was watching when the exploit attempt hit the mempool, and it moved faster, submitting a competing transaction with a higher gas fee that ensured it landed in the block first.

The result: Yoink captured the rsETH – a liquid restaking token issued by Kelp DAO representing restaked ETH – before the original attacker’s transaction could complete. The attacker spent gas, exposed their strategy, and ended up with nothing. The $7.7 million in rsETH landed in Yoink’s wallet instead.

rsETH is Kelp DAO’s receipt token for users who deposit ETH or liquid staking tokens into the protocol’s restaking infrastructure. It carries underlying value tied to staked positions, which makes it a meaningful target – and also means any movement of large rsETH quantities is quickly visible to anyone monitoring on-chain activity.

Kelp’s Response and What It Means for Restaking Security

Kelp DAO responded by temporarily freezing the address that received the rsETH. Freezing an address at the token contract level prevents further transfers from that wallet, a capability built into some token standards that gives protocol teams an emergency brake when funds are moving somewhere they shouldn’t be. Whether that mechanism is applied to MEV-captured funds – where the party holding the tokens is not the original attacker – raises complicated questions about what “recovery” actually looks like here.

The frozen address belongs to Yoink, not the exploiter. Yoink is an MEV bot, meaning it operates autonomously according to programmed rules. It did not plan or initiate the exploit – it recognized a profitable transaction in the mempool and executed a front-run. That behavior is standard in Ethereum’s current architecture, and whether Yoink’s operator is entitled to those funds, or whether Kelp can and should claw them back, depends on both the technical parameters of the freeze and whatever negotiations or on-chain governance steps follow.

Kelp’s freeze is described as temporary, which suggests the team is buying time rather than declaring a resolution. The underlying vulnerability in the custom Safe module presumably still needs to be identified, patched, and disclosed – the attack attempt proved the surface exists, even if no one successfully exploited it in the conventional sense.

MEV bots have a complicated reputation in the Ethereum ecosystem. Critics argue they extract value from ordinary users, increasing costs and occasionally causing failed transactions. Supporters point out that bots like Yoink, in scenarios like this one, act as a kind of accidental circuit breaker – the same infrastructure that front-runs retail traders also front-runs thieves. This incident doesn’t resolve that debate, but it does add a concrete data point to it: $7.7 million in user funds did not end up in an exploiter’s wallet, at least not yet.

The more pointed question is how Kelp DAO’s protocol allowed the exploit attempt to reach the mempool in the first place. A custom Safe module is not a default configuration – someone built it, deployed it, and integrated it into the protocol’s security architecture. That module apparently had a flaw significant enough for an attacker to construct a transaction around. The MEV bot’s speed obscures the fact that the vulnerability existed at all.

Where the Funds Sit Now

With the receiving address frozen and $7.7 million in rsETH sitting in Yoink’s wallet, the situation is functionally unresolved. Kelp has the technical leverage to prevent movement, but the bot’s operator holds the actual position – and if the freeze is lifted without a coordinated return, that rsETH goes somewhere. Whether Kelp can compel a return, negotiate one, or pursue any legal or on-chain mechanism to recover the tokens is the operative question hanging over the incident.

The attacker who initiated the exploit attempt is still unidentified, their original target wallet still unclear, and the specific Safe module vulnerability still unpatched publicly – which means anyone who spotted the original exploit attempt in the mempool now knows roughly what to look for.