Tigris Trade contest - 0xmuxyz's results

Lines of code

https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L101 https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L336

Vulnerability details

Impact

The NFT may get stuck in the contract that does support ERC721.

Proof of Concept

• _transfer() function is used for ERC721 in the following lines:
  • https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/GovNFT.sol#L101
  • https://github.com/code-423n4/2022-12-tigris/blob/main/contracts/BondNFT.sol#L336

There are certain smart contracts that do not support ERC721, using _transfer() may result in the NFT being sent to such contracts.

This lead to that the NFT may get stuck in the contract that does support ERC721.

Tools Used

• Manual Review

Recommended Mitigation Steps

• Consider using _safeTransfer() instead of using _transfer() for ERC721. https://docs.openzeppelin.com/contracts/4.x/api/token/erc721#ERC721-_safeTransfer-address-address-uint256-bytes-