Cairo-Contracts are OpenZeppelin Contracts written in Cairo for Starknet, a decentralized ZK Rollup. This vulnerability can lead to unauthorized ownership transfer, contrary to the original owner's intention of leaving the contract without an owner. It introduces a security risk where an unintended party (pending owner) can gain control of the contract after the original owner has renounced ownership. This could also be used by a malicious owner to simulate leaving a contract without an owner, to later regain ownership by previously having proposed himself as a pending owner. This issue has been addressed in release version 0.16.0. All users are advised to upgrade. There are no known workarounds for this vulnerability.