Submitted by gpersoon, also found by cmichel.
The function transferNotionalFrom of VaultTracker.sol uses temporary variables to store the balances.
If the from and to address are the same then the balance of from is overwritten by the balance of to.
This means the balance of from and to are increased and no balances are decreased, effectively printing money.
Note: transferNotionalFrom can be called via transferVaultNotional by everyone.
https://github.com/Swivel-Finance/gost/blob/v2/test/vaulttracker/VaultTracker.sol#L144-L196
https://github.com/Swivel-Finance/gost/blob/v2/test/marketplace/MarketPlace.sol#L234-L238
Add something like the following:
require (f != t,"Same");
JTraversa (Swivel) confirmed
