Submitted by saian, also found by 0x4non, Ch_301, davidbrai, izhuer, MEP, Picodes, PwnPatrol, R2, rotcivegaf, scaraven, and Soosh
aftertokenTransfer in ERC721Votes transfers votes between user addresses instead of the delegated addresses, so a user can cause overflow in _moveDelegates and get unlimited votes.
https://github.com/code-423n4/2022-09-nouns-builder/blob/7e9fddbbacdd7d7812e912a369cfd862ee67dc03/src/lib/token/ERC721Votes.sol#L268
https://github.com/code-423n4/2022-09-nouns-builder/blob/7e9fddbbacdd7d7812e912a369cfd862ee67dc03/src/lib/token/ERC721Votes.sol#L216
During delegation balanceOf(from) amount of votes transferred are to the _to address
When user1 delegates to another address balanceOf(user1) amount of tokens are subtraced from user2s votes, this will cause underflow and not revert since the statements are unchecked
Foundry
Change delegate transfer in afterTokenTransfer to
Alex the Entreprenerd (judge) increased severity to High and commented:
tbtstl (Nouns Builder) confirmed
