mahdikarimi - removed collateral can't be accessible

[sherlock-admin]

mahdikarimi

medium

removed collateral can't be accessible

Summary

If admin remove a collateral , the collateral can't be accessible anymore .

Vulnerability Detail

Since the collateral will be removed from CollateralInfo array so it can't be used for re-balancing therefore removing collateral leads to just ignoring it while re-balancing , while there should be a mechanism to swap it to other collaterals .

Impact

removed collateral won't be accessible

Code Snippet

https://github.com/sherlock-audit/2023-05-USSD/blob/main/ussd-contracts/contracts/USSD.sol#L120-L123

Tool used

Manual Review

Recommendation

Add a mechanism to swap collateral to another allowed collateral after removing .

Duplicate of #341