Valid low, since `_ENTRYPOINT` is defined by deployer within the `Nexus.sol` [contract](https://github.com/Cyfrin/2024-07-biconomy/blob/9590f25cd63f7ad2c54feb618036984774f3879d/contracts/Nexus.sol#L76), so even if unchanged the account could still be used. The only current supported entry point contract would be [here](https://github.com/eth-infinitism/account-abstraction/blob/develop/contracts/core/EntryPoint.sol#L605). Additionally `Nexus.sol` is an upgradeable contract, so entrypoint can be changed, so one can argue the severity of this issue could be downgraded lower.