Submitted by unforgiven, also found by GimelSec, and zzzitron
https://github.com/Badger-Finance/vested-aura/blob/d504684e4f9b56660a9e6c6dfb839dcebac3c174/contracts/MyStrategy.sol#L107-L113
https://github.com/Badger-Finance/vested-aura/blob/d504684e4f9b56660a9e6c6dfb839dcebac3c174/contracts/MyStrategy.sol#L405-L413
https://github.com/Badger-Finance/vested-aura/blob/d504684e4f9b56660a9e6c6dfb839dcebac3c174/contracts/MyStrategy.sol#L421-L425
If the value of bribesProcessor was 0x0 (the default is 0x0 and governance()  can set to 0x0) then attacker can call sweepRewardToken() make contract to send his total balance in attacker specified token to 0x0 address.
The default value of bribesProcessor is 0x0 and governance can set the value to 0x0 at any time. Rewards are stacking in contract address and they are supposed to send to bribesProcessor.
This is sweepRewardToken() and _handleRewardTransfer() and _sendTokenToBribesProcessor() code:
As you can see calling sweepRewardToken() eventually (sweepRewardToken() -> _handleRewardTransfer() -> _sendTokenToBribesProcessor()) would transfer reward funds to bribesProcessor and there is no check that bribesProcessor!=0x0 in execution follow. so attacker can call sweepRewardToken() when bribesProcessor is 0x0 and contract will lose all reward tokens.
VIM
Check the value of bribesProcessor in _sendTokenToBribesProcessor().
Alex the Entreprenerd (BadgerDAO) confirmed and commented:
jack-the-pug (judge) validated
