Inheritable Smart Contract Wallet

Summary

The expression:
uint256 finalAmount = (value / divisor) * multiplier; in the contract InheritanceManager::buyOutEstateNFT
is vulnerable to precision loss due to Solidity’s integer division behavior. Since Solidity truncates decimals in division, any remainder from value / divisor is discarded before multiplying by multiplier. This can result in incorrect fund distribution, rounding errors, or unintended discrepancies in calculations.

Vulnerability Details

The expression:
uint256 finalAmount = (value / divisor) * multiplier; in the contract InheritanceManager::buyOutEstateNFT
is vulnerable to precision loss due to Solidity’s integer division behavior. Since Solidity truncates decimals in division, any remainder from value / divisor is discarded before multiplying by multiplier. This can result in incorrect fund distribution, rounding errors, or unintended discrepancies in calculations.

Impact

The contract might underpay or overpay and The error accumulates when dealing with large sums or multiple transactions.consider an example where it breaks

Tools Used

Recommendations

A better approach would be multiplication First to Avoid Precision Loss.uint256 finalAmount = (value * multiplier) / divisor;
more accurate than the original approach.

orginal approach - uint256 finalAmount = (value / divisor) * multiplier;

After refactor - uint256 finalAmount = (value * multiplier) / divisor;