Submitted by sashik_eth
instantUnstake() allows user to unstake their stakingToken for a fee paid to the liquidity providers. This fee could be changed up to 100% any moment by admin.
Malicious admin could frontrun users instantUnstake() transaction and set fee to any value (using setFee()) and get all users unstaking asset.
Its even could lead to a situation when non-malicious admin accidentally frontrun unstaking user by increasing fee to a new rate, which user wasnt expected.
Consider introducing an upper limit for fees so users can know the maximum fess available in protocol and adding timelock to change fee size.
This way, frontrunning will be impossible, and users will know which fee they agree to.
toshiSat (Yieldy) acknowledged 
JasoonS (judge) commented:
