# ClearingHouse::addEngine() initializes productEngine, so it may be frontrunned and someone initializes productEngine instead Low/Info · Three Sigma · Hybrid orderbook DEX · 3rd April 2024 Finding 3S-Vertex-L08 of the Vertex security review. - Report: /reports/vertex - Source: https://github.com/0xsimao/audits/blob/main/Three%20Sigma/2024-04-03-vertex.pdf --- ### Description ClearingHouse::addEngine() initializes productEngine, which means it is uninitialized prior to the call. Thus, someone may spot the uninitialized productEngine proxy and initialize it themselves, making the addEngine() call revert. ### Recommendation Send the productEngine creation and ClearingHouse::addEngine() atomically, via a multicall or custom contract deployer. ### Status Acknowledged Disclosed by 0xSimao (https://0xsimao.com/).