Core Contracts

Summary

Expired boost delegations or near expired boost can be re-delegated

Vulnerability Details

delegateBoost falis to ensure that the boost that is being delegated is infact a valid delegation not expired as no checks are done for the expiry of the delegation this open an opportunity for an malicious actor to delegate expired boost and which will be extended by delegation.expiry = block.timestamp + duration;

Impact

Malicious actor can delegate their boost and make it brand new leading to the unfair advantages and gaining boost which should not be applicable.
This will effect reward distributions and calculations

Recommendations

Impose a require statement that ensure the check that expired boost can't be redelegated and make the transaction revert.