Tadle

Summary

Reducing refferer's extra rates does not affect the existing fees paid.

Vulnerability Details

Scenario
- Alice has refferal bonus of 45% (30 base and 15 extra)
- An admin decides to reduce her bonus by calling: SystemConfig::updateReferralExtraRateMap(). The extra rate is now 5%
- Alice still uses her old refferal bonus and does not pay the higher fees due to the smaller refferer bonus

Code snippets

https://github.com/Cyfrin/2024-08-tadle/blob/main/src/core/SystemConfig.sol#L199-L207

https://github.com/Cyfrin/2024-08-tadle/blob/main/src/core/SystemConfig.sol#L41-L46

Impact

The existing users pay the same fees, as before, even though the fees were increased by reducing the refferal bonus. The protocol loses fee gains.

Tools Used

Manual review

Recommendations

Implement a mechanism for adjusting the existing refferal bonuses, after the extra rate bonus has been reduced by the admin.