Submission Details
Severity:
No Reentrancy Protection in claimReward
Summary
The function sends Ether to the user before updating internal state, violating the checks-effects-interactions pattern. This enables classic reentrancy attacks.
Vulnerability Details
function claimReward() public {
payable(msg.sender).transfer(rewardAmount);
rewardAmount = 0;
}
A malicious contract could use a fallback function to re-enter the claim and drain funds multiple times.
Impact
Complete contract drain via reentrancy.
Tools Used
Manual audit
Foundry fallback-based reentrancy simulation
Recommendations
Use ReentrancyGuard and correct ordering:
function claimReward() public nonReentrant {
uint256 amount = rewardAmount;
rewardAmount = 0;
payable(msg.sender).transfer(amount);
}
Rewards breakdown
nSLOC
349This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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