Submission Details
Severity:
Storage collision in Implementation contracts
summary
Wrong storage slots usage or storage collision
vulnerability details
In LevelTwo which is the v2 implementation contract , the below state variable has been removed
uint256 schoolFees;
uint256 public immutable reviewTime = 1 weeks;
uint256 public sessionEnd;
mapping(address => uint256) private reviewCount;
mapping(address => uint256) private lastReviewTime;
-> Proxy stores data based on the storage slots of the implementation contract , but here when we have removed some of the state variables then there is a problem of overwriting one state varialbe with another
-> We only need to add a new variables at the end of the state variables , but should not delete or add any in the miidle of the storage slots (state variables)
impact - High
likelyhood - High
Recommendations
-> Follow this one for storage slots in proxy contracts
Rewards breakdown
nSLOC
243This contest has a flat reward structure with the following payouts:
100 EXP
20 EXP
2 EXP
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