Summary

Substraction without prior checking

Vulnerability Details

In _redeem_collateral:

self.user_to_token_address_to_amount_deposited[_from][ token_collateral_address ] -= amount_collateral

If amount_collateral exceeds the user’s balance, an underflow occurs.

Impact

Failing to validate subtractions can lead to underflows, allowing users to redeem more collateral than they deposited or burn more DSC than they minted.

Tools Used

N/A

Recommendations

assert self.user_to_token_address_to_amount_deposited[_from][token_collateral_address] >= amount_collateral, "Insufficient collateral balance"

This ensures the user has enough collateral in their balance before proceeding with the subtraction.