Aave v3 exploit drains up to $310K after Safe module attack

An attacker drained two Safe multisig wallets on Ethereum on October 1, 2026. They did it by exploiting a third-party module built to run leveraged positions on Aave v3.

Security firm SlowMist flagged the attack. It reported that the exploiter forged Safe authentication and repaid about 1,300 WETH of Aave debt to unlock the wallets’ collateral. Combined victim losses are estimated between $305K and $310K.

Neither Aave v3 nor Safe’s core infrastructure was compromised. The weak link was the FlashLoopAdapter, a module the victims had enabled on their own wallets.

How the FlashLoopAdapter attack worked

The vulnerable component was the FlashLoopAdapter, a module designed to help users build leveraged positions on Aave v3. It gets limited permission to operate the account so the owner doesn’t have to do every step by hand.

The attacker deployed a fake contract that impersonated Safe authentication. That let them slip past the module’s access controls. From there, they steered the module’s execution paths to move assets out of the two multisigs.

The whole operation ran in a single transaction. It started with a WETH flash loan sourced from Morpho.

With the borrowed funds, the attacker paid down roughly 1,300 to 1,335 WETH of Aave debt held by the wallets. Repaying a loan frees up the collateral behind it, and that collateral was the real prize.

From one Safe, the attacker pulled collateral worth around 1,306.48 WETH. A smaller sum came out of the second wallet. After repaying the flash loan, the attacker’s net profit landed at approximately 114.09 ETH.

The root cause: trusting the caller

Post-incident analyses traced the flaw to the module’s open() and close() functions. These are the routines that set up and unwind leveraged positions.

The specific problem was weak validation of responses controlled by the caller. The module accepted answers from whoever called it without properly confirming they came from a legitimate Safe.

SlowMist and fellow security firm ExVul both raised alerts after the attack. Both affected Safes disabled the vulnerable module right away to stop further losses.

Why modules keep becoming the weak spot

Safe wallets are popular precisely because they are modular. Owners can attach extensions that automate strategies, manage permissions or connect to lending protocols like Aave.

A module with broad execution rights over a wallet effectively inherits that wallet’s power. If the module has a bug, the multisig’s signature requirements don’t help much, because the module was already granted a way around them.

What this means for DeFi users and builders

For users running leveraged strategies through third-party tooling, the security of a position is only as strong as the least-audited contract with permission to touch it.

Holders of Safe multisigs may want to review which modules are enabled on their wallets. Any module that can move funds deserves the same scrutiny as the wallet’s signer set, arguably more, since it can act without collecting signatures.

For Aave, the protocol worked as designed: debt was repaid, so collateral was released. The failure sat entirely in the adapter that decided who was allowed to trigger those actions.

For developers building leverage tools and wallet extensions, validating every caller-supplied input, especially anything claiming to come from a trusted contract, is the minimum. Flash loans mean attackers can bring enormous temporary capital to any flaw, so even narrow bugs can unlock large balances.

Disclosure: This article was edited by Estefano Gomez. For more information on how we create and review content, see our Editorial Policy.