Core Contracts
Regnum Aurum Acquisition Corp
HardhatReal World AssetsNFT
77,280 USDC
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Submission Details
Severity: medium
Valid

The calculateDustAmount Function Overestimates Total Obligations thus Making Excess Funds Appear Nonexistent

victortheoracle

Summary

The calculateDustAmount function in RToken.sol applies the liquidity index twice, making the protocol’s total obligations appear larger than they actually are.

Vulnerability Details

The problematic line:

https://github.com/Cyfrin/2025-02-raac/blob/89ccb062e2b175374d40d824263a4c0b601bcb7f/contracts/core/tokens/RToken.sol#L325

uint256 totalRealBalance = currentTotalSupply.rayMul(ILendingPool(_reservePool).getNormalizedIncome());

Since currentTotalSupply returns totalSupply which is already in a scaled form, multiplying by getNormalizedIncome() scales it again, inflating the obligation amount.

https://github.com/Cyfrin/2025-02-raac/blob/89ccb062e2b175374d40d824263a4c0b601bcb7f/contracts/core/tokens/RToken.sol#L203-L205

function totalSupply() public view override(ERC20, IERC20) returns (uint256) {
return super.totalSupply().rayMul(ILendingPool(_reservePool).getNormalizedIncome());
}

Impact

This miscalculation makes dust funds appear nonexistent, as totalRealBalance will always be greater than contractBalance. As a result, the function will always return 0, meaning no excess funds will ever be recognized. This leads to unclaimed tokens being left in the contract indefinitely.

Tools Used

  • Manual code review

Recommendations

Ensure that currentTotalSupply is only scaled once by checking its original form.

Updates

Lead Judging Commences

inallhonesty Lead Judge 6 months ago
Submission Judgement Published
Validated
Assigned finding tags:

RToken::calculateDustAmount incorrectly applies liquidity index, severely under-reporting dust amounts and permanently trapping crvUSD in contract

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