An attacker exploited a custom FlashLoopAdapter access control flaw to drain approximately $305,000 to $310,000 from two Safe wallets on Ethereum, according to reports from Defimon Alerts. The attacker exploited an authentication flaw in the FlashLoopAdapter contract, which allowed a fake Safe to pass checks meant to restrict access to wallets that had enabled the module. The incident was detected at 15:08:57 UTC on October 1 by Defimon Alerts, which reported that Aave v3 itself was not affected by the exploit. The attacker deployed a fake contract that impersonated Safe authentication, allowing them to slip past the module's access controls and steer the module's execution paths to move assets out of the two multisigs.
The attacker used a Morpho flash loan to repay approximately 1,335 WETH in Aave debt belonging to the first Safe wallet, identified as 0xcfedf95a3653a128dfc2e4288758a1a1850d169f. This debt repayment freed collateral tied to the leveraged Aave position, allowing the attacker to withdraw approximately 1,306.48 weETH to an attacker-controlled address. A second Safe wallet, 0xe3b23e47df7cd85876ac6cb05bdb9d7cd5b28520, lost an additional 6.4 weETH through the same vulnerable module. Both affected Safes shared the same single owner, as reported by Defimon Alerts. After repaying the flash loan, the attacker's net profit landed at approximately 114.09 ETH, valued at around $305,000 to $310,000 when the incident was reported. An Etherscan transaction identified in the security alert shows the activity involving the first affected Safe, with the transaction recording the burning of approximately 1,306.48 variableDebtEthWETH and withdrawal of 1,306.48 weETH from Aave. The distinction between gross movement and realized loss is material - the large collateral withdrawal enabled the debt repayment and position unwind, with the reported net proceeds being the ETH remaining after those transaction steps.
According to SlowMist and ExVul, the weakness was found in the access controls used by the adapter's open() and close() functions. The specific problem was weak validation of responses controlled by the caller, where the module accepted answers from whoever called it without properly confirming they came from a legitimate Safe. The attacker's contract acted as the flash liquidity provider and used the _swap() function to call a swapRouter using caller-supplied swapCalldata, allowing both inputs to be controlled by the attacker. The entire operation ran in a single transaction, starting with the WETH flash loan sourced from Morpho and ending with the successful asset extraction. Flash loans allow contracts to temporarily access liquidity within a single transaction, with the borrowed amount and applicable fee required to be returned or otherwise settled before the transaction completes, as documented by Aave. The AAVE hack attacker-controlled contract also supplied the adapter's swap router and calldata, pointing the router at a victim Safe and setting the calldata to invoke execTransactionFromModule. Because FlashLoopAdapter was already enabled on that Safe, the wallet accepted the call as an authorized module transaction, turning a narrow authentication flaw into access to wallet-controlled collateral.
Aave founder and CEO Stani Kulechov confirmed that the affected contract was a third-party external adapter built on top of Aave and had zero effect on Aave v3. FlashLoopAdapter is a separate custom contract that uses Aave v3 to manage leveraged positions held through Safe wallets, with the reported vulnerability concerning how the adapter authenticated callers and what they could make the enabled module execute. This distinction mirrors other incidents where protocols remained operational while third-party modules provided the attack route, as seen in previous incidents involving SquidRouterModule and Gnosis Pay's Zodiac delay module. The protocol worked as designed, with debt being repaid so collateral was released, but the failure sat entirely in the adapter that decided who was allowed to trigger those actions. The case is therefore a DeFi security failure at the integration layer, not evidence that Aave V3's lending pools were compromised. Safe modules can execute wallet transactions without requiring the standard owner transaction flow each time, which supports automation but also gives an authorized module a route to wallet assets. The episode underscores how wallet permissions and execution paths matter alongside the security of the lending protocol itself, a concern also central to custody infrastructure and authentication controls.
SlowMist identified the attacker address as 0x42c2633438609881c8fBAb82414eb9A0c45F9353, while the vulnerable FlashLoopAdapter contract was listed as 0x16bb8b912da187870c23ec6756bb3fad061283d8. The attacker retained approximately 114.09 ETH after the transaction, valued at around $305,000 to $310,000 when the incident was reported. SlowMist separately estimated the loss at 114.09 ETH and noted that roughly 1,300 WETH of debt was repaid during the collateral unlocking process, with much of the capital moved through the transaction tied to repaying debt and unwinding the leveraged position before remaining assets could be taken. Both affected Safes disabled the vulnerable module right away to stop further losses. The FlashLoopAdapter investigation remains ongoing, and it is not yet clear whether additional wallets or contracts were affected. This incident follows a separate September Safe-wallet incident involving roughly 2,900 rsETH and weak authorization in an executor connected to an enabled module, though the two incidents involved distinct contracts and attack paths.
