An attacker can front-run any operation that depends on the pool contracts internal balance amounts being unsynced to pools balance on token/base contracts effectively nullifying the transfer of base/tokens for those operations. This will make _getAddedBaseAmount() and _getAddedTokenAmount() return 0 (because the balances are synced) from such operations.
The affected operations are: addForMember(), swapTo() and mintSynth() which will all take the user funds to respective contracts but will treat it as 0 (because of the syncing) and thus not add liquidity, return swapped tokens or mint any synths to the affected users. User loses deposited funds to the contract.
Recommend adding access control to sync() function so that only Router can call it via addDividend().
verifyfirst (Spartan) confirmed and disagreed with severity:
SamusElderg (Spartan) commented:
ghoul-sol (judge) commented:
