Submitted by cmichel, also found by tensors
ERC1155 tokens have a callback on transfer, making reentrancy a possibility.
I havent been able to find any reentrancy, but having extra external function calls isnt safe.
If its necessary to use an ERC1155 there is nothing you can do about it, but otherwise consider just using an ERC20.
See actions/ERC1155Action sol.
Recommend confirming that using tokens with callbacks is really necessary for the protocol to function.
jeffywu (Notional) disputed and disagreed with severity:
ghoul-sol (judge) commented:
