A crypto user lost millions in a failed Aave swap after trying to convert $50.4 million USDT into the AAVE token through CoW Protocol and SushiSwap. Instead of receiving a large AAVE position, the wallet got only 327 AAVE, worth about $36,000, according to Etherscan.
The failed crypto swap also drew a MEV bot. The bot targeted the large order, pushed the AAVE price higher before execution, and then sold into the move. As a result, the bot made about $9.9 million from the trade.
After the transaction, Aave founder Stani Kulechov and CoW DAO said the user had seen clear slippage warnings before confirming the order. Both said the trader accepted the risk and still proceeded with the swap.
MEV Bot Exploits Aave Swap During Huge Crypto Swap
The wallet had recently received the funds from Binance. Then it tried to swap the full $50.4 million amount from USDt (USDT) into the AAVE token. The trade went through CoW Protocol and SushiSwap, but the execution failed badly.
According to the onchain data, the wallet received only 327 AAVE. At the time, AAVE traded near $114. That means the user effectively paid about $154,000 per token in the failed Aave swap.
At the same time, a MEV bot attacked the trade with a sandwich attack. In this type of move, a bot spots a large pending order, buys first to lift the price, and then sells after the victim’s order fills at a much worse rate.
The bot reportedly used a $29 million flash loan in wrapped Ether (ETH) from Morpho. Then it bought AAVE on Bancor, pushed the token price up, and later sold the inflated tokens on SushiSwap. That trade produced about $9.9 million in profit.
Slippage Warning Appeared Before the CoW Protocol Trade
After the failed crypto swap, Stani Kulechov said the user had been warned about the size of the trade and the likely execution problem. He wrote on X that the protocol interface flagged “extraordinary slippage” because of the “unusually large size of the single order.”
Kulechov also said,
“The user confirmed the warning on their mobile device and proceeded with the swap, accepting the high slippage, which ultimately resulted in receiving only 324 AAVE in return.”
While the earlier transaction data showed 327 AAVE, his post referred to 324 AAVE.
That detail does not change the outcome. The trade still resulted in an almost total crypto swap loss. The key issue was the gap between the size of the order and the liquidity available for the AAVE token across the pools used in the transaction.
Automated market makers like SushiSwap use pricing formulas that react to trade size and liquidity depth. So when a user sends a very large order into a shallow market, slippage can become extreme. In this case, the MEV bot made the situation even worse.
CoW Protocol Says No Market Could Fill the AAVE Token Order Properly
CoW DAO also responded on X after the trade. It said the user saw direct warnings showing that the order would erase nearly all of its value. The DAO added that the trader had to explicitly choose to continue.
CoW DAO said,
“Despite clear warnings that showed the user they would lose nearly all of the value of their transaction, and despite needing to explicitly opt into the trade after seeing the warning, the user chose to proceed with their swap.”
The DAO also said,
“No DEX, DEX aggregator, public liquidity pool, or private liquidity pool (or combination thereof) would have been able to fill this trade at anywhere near a reasonable price.”
That statement pointed to a broader liquidity problem around the size of the Aave swap.
Later, CoW DAO said it would refund any protocol fees tied to the transaction. Aave also said it would try to contact the user and return $600,000 in fees collected from the swap.
Aave and CoW DAO Responses Add More Detail to the Crypto Swap Loss
The failed Aave swap quickly became a major example of how a large onchain order can break down. First, the trade faced extreme slippage. Then a MEV bot used that setup to extract more value through a sandwich attack.
The onchain record on Etherscan showed the final result clearly. A wallet funded with $50.4 million USDT attempted to buy the AAVE token but received only a few hundred tokens. Meanwhile, the bot that exploited the order walked away with nearly $10 million.
Kulechov later wrote,
“The key takeaway is that while DeFi should remain open and permissionless, allowing users to perform transactions freely, there are additional guardrails the industry can build to better protect users.”
Disclosure:This article does not contain investment advice or recommendations. Every investment and trading move involves risk, and readers should conduct their own research when making a decision.
Kriptoworld.com accepts no liability for any errors in the articles or for any financial loss resulting from incorrect information.
Tatevik Avetisyan is an editor at Kriptoworld who covers emerging crypto trends, blockchain innovation, and altcoin developments. She is passionate about breaking down complex stories for a global audience and making digital finance more accessible.
📅 Published: March 13, 2026 • 🕓 Last updated: March 13, 2026
