Summary

when call upgradeTier no check amount>=minted

Vulnerability Details

amountis a maximum number of members in tier. mintedthe number of members who are in the tier.

it is very important that the number of members does not exceed the allowed amount. When upgrade to a higher tier, it is not checked if the allowable amount is not exceeded when adding a new user. Check is important to maintain a balanced distribution of profit

Recommendations

add check