I have sorted out the recent $50 million transaction incident on Aave. (Through CoW Swap) Although this is the most severe transaction execution loss in DeFi history, it happened strangely. The first point is that CoW's resistance to MEV has almost failed. According to the current liquidity of AAVE on the chain, it is definitely not a problem to switch back to AAVE with $5 million, but the final execution was routed to the worst depth Sushi pool with only $70000 in liquidity. The result was to spend 50 million US dollars and only purchase 36000 US dollars of AAVE. CoW disclosed some issues in the report, such as a bug in the gas cap, where a solver provided a better quote but was blocked by this restriction. The issue was later fixed. But this transaction accident is irreparable. In the execution phase, there is still a chance to save the market. Solver E found a better offer at this stage and successfully won the auction, but ultimately did not submit the transaction. CoW's auction system does not have emergency measures or punishment mechanisms for situations where the winner fails to deliver after winning, even if they refuse the transaction. Finally, it was left to a very poor solver to take over. The second strange thing is that a single transaction as large as $50 million is rare in non stablecoin exchanges. Because most pools cannot support liquidity, and in the case where the protocol has already alerted 99% of the price impact, users manually confirm transactions. The third point is that CoW claimed that this transaction may have leaked to the public mempool, but the specific reasons have not been clearly stated yet. At present, both protocols have issued post event reports, with MEV bot profiting $9.9 million and bribing block builders with $34 million. The responsibility determination is very clear, mainly in CoW, because Aave only integrates CoW components in the front-end, and the two protocols do not shift responsibility or engage in arguments. I think their attitude is very good. This incident was caused by multiple system issues overlapping, resulting in a worse outcome than the worst-case scenario. There are still many issues that need to be investigated for CoW. At present, the executor of this transaction seems to have not appeared, and the initial motive for making this transaction is also unknown.