[Lines of code](https://github.com/code-423n4/2022-09-canto/blob/65fbb8b9de22cf8f8f3d742b38b4be41ee35c468/src/Swap/BaseV1-periphery.sol#L532) # Vulnerability details ## Impact Currently, it calculates token price with the amount of decimals [here](https://github.com/code-423n4/2022-09-canto/blob/65fbb8b9de22cf8f8f3d742b38b4be41ee35c468/src/Swap/BaseV1-periphery.sol#L532) and normalizes using 1e18 after that. There are some irregular tokens with small decimals and the token price might be calculated wrongly. ## Proof of Concept As we can see [here](https://github.com/d-xo/weird-erc20#low-decimals), some tokens have very low decimals. So the below scenario would be possible. Let me explain with [getPriceCanto()](). It calls [_getAmountOut()]() for price calculation. 1. TokenA = Canto token has 18 decimals typically. Let assume reserveA = 1e20 for [this calculation](). 2. TokenB = WeirdToken has 4 decimals and reserveB = 1e23. 3. So when we calculate price with decimals = 10000 [here](https://github.com/code-423n4/2022-09-canto/blob/65fbb8b9de22cf8f8f3d742b38b4be41ee35c468/src/Swap/BaseV1-periphery.sol#L532>), price will be 1e4 * 1e23 / (1e20 + 1e4) = 1e23 / (1e16 + 1) from [this formula](), it will be 1e18 * 1e23 / (1e20 + 1e18) = 1e23 / (1e2 + 1) = 1e37 / (1e16 + 1e14) from [this formula](

There is a problem with price calculation using BaseV1Pair._getAmountOut.