Could you please explain, is there a need to use a ReentrancyGuard modifier if the contract follows the CEI(Check Effect Interactions) pattern? If yes, could you bring an example, where the contract follows the CEI pattern, but still is vulnerable to reentrancy attacks? Thanks


1 Answer 1


Even if you're using CEI in your smart contracts, consider adding ReentrancyGuard for extra security. While CEI helps, it doesn't guarantee complete protection.

Human error and complex interactions can still pose risks, making ReentrancyGuard a valuable additional layer of defense against potential exploits. Remember, security is about layering, and ReentrancyGuard enhances your contract's resilience.

The DAO hack in 2016 exploited a similar reentrancy vulnerability in a complex contract, leading to a loss of $60 million. For further insight and an example, check out this blog: https://blog.chain.link/reentrancy-attacks-and-the-dao-hack/

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.