Fjord Token Staking

Summary: The contract may not correctly handle tokens that implement fees on transfer, leading to incorrect tracking of staked amounts.

• Vulnerability Details: Some ERC-20 tokens deduct a fee when they are transferred, meaning the amount received by the contract could be less than the amount sent. The current contract logic appears to assume that the full amount sent is received, which could lead to incorrect accounting of user balances and potential loss of rewards for users.

• Impact: Users who stake fee-on-transfer tokens may find that their staked amount is lower than expected, leading to reduced rewards or even loss of principal. This could also cause discrepancies in the contract’s overall balance.

• Tools Used: Manual code review.

• Recommendations: Implement a check after token transfers to confirm the exact amount received by the contract. Adjust the user’s staked balance accordingly to reflect any transfer fees.