Aave and CoW Swap issue separate post-mortems on $50.4 million March 12 DeFi swap loss

On March 12, a user swapped about $50.4 million in aEthUSDT for roughly $36,000 in aEthAAVE via Aave's interface using a CoW Swap-powered widget. Aave later attributed the loss to extreme illiquidity and introduced a new "Aave Shield" protection, while CoW Swap detailed a chain of infrastructure failures and a suspected private mempool leak. On-chain data also shows major MEV extraction from the transaction and has revived questions about Aave's 25-basis-point swap fee flows.