DeFi Smart Contract Vulnerabilities Audit Guide

Here are three specific DeFi smart contract vulnerabilities suitable for inclusion in a professional audit report, including technical descriptions, impact analysis, and remediation recommendations.

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1. Reentrancy Attack via Unvalidated State Updates

Description:

This vulnerability occurs when a smart contract makes an external call to an untrusted contract (e.g., calling transfer() on an ERC-20 token) before updating its internal state variables (e.g., user balances or withdrawal limits). If the external contract is malicious, it can re-enter the vulnerable function during the execution of the external call, exploiting the stale state to bypass logic checks.

Technical Example (Solidity):

function withdraw(uint amount) external {
    // Vulnerable: State update happens AFTER external call
    payable(msg.sender).transfer(amount); 
    balance[msg.sender] -= amount; 
}

A malicious contract can implement a receive() function that calls `