Slow Mist Detects EIP-7702 Exploit: QNT Reserve Pool Loses 1,988.5 QNT (~$54.93M in ETH)

Gate News message, April 29 — Slow Mist detected a malicious transaction exploiting a vulnerability in an EIP-7702 account, resulting in the loss of 1,988.5 QNT (approximately 54.93 ETH) from a QNT reserve pool.

The vulnerability stemmed from a structural flaw in the reserve pool's access control. An administrator EOA address delegated its code to a BatchExecutor contract via the EIP-7702 mechanism. The BatchExecutor contract then designated an unpermissioned BatchCall contract as an authorized caller. However, the BatchCall.batch() function lacked any permission checks, creating an arbitrary call vulnerability.

Attackers exploited this gap to execute unauthorized calls against the reserve pool and steal QNT tokens. The incident highlights risks associated with improper delegation and insufficient permission validation in smart contract design, particularly when using EIP-7702's code delegation feature.