Summary

There is no minimum arbiterFee. So, a buyer can create an escrow with arbiterFee = 0. An honest arbiter will still resolve the dispute in exchange for nothing.

Vulnerability Details

In the constructor of Escrow, there are validations for the important variables but no validation on the arbiterFee. Only validation for arbiterFee is that it should be less than price. It means it's okay to create an Escrow with arbiterFee = 0, even in cases where arbiter != address(0).

An honest arbiter will still choose to resolve the dispute(as he sees that otherwise funds will be stuck in the Escrow) in exchange for nothing.

Impact

Arbiter will get nothing in exchange for his service

Tools Used

Manual review

Recommendations

There should be some minimum arbiterFee.
Ideally arbiterFee should be some percentage of price