Submission Details
Severity:
Reentrancy vulnerability in `GivingThanks::donate` function, enabling malicious users to mint multiple NFTs in one donation
Summary
In the implementation, the GivingThanks::donate function doesn't follow CEI(Check - Effect - Interact) pattern, allowing reentrancy attacks. Although the second charity.call will fail due to balance is not enough, it's still a good practice to follow CEI pattern.
Impact
Users are enable to donote 0 eth and mint multiple NFTs by an reentrancy attack.
Recommendation
Follow CEI pattern
function donate(address charity) public payable {
require(registry.isVerified(charity), "Charity not verified");
_mint(msg.sender, tokenCounter);
// Create metadata for the tokenURI
string memory uri = _createTokenURI(msg.sender, block.timestamp, msg.value);
_setTokenURI(tokenCounter, uri);
tokenCounter += 1;
(bool sent,) = charity.call{value: msg.value}("");
require(sent, "Failed to send Ether");
}
Rewards breakdown
nSLOC
67This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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