Christmas Dinner

Summary:

The changeHost function does not check if _newHost is the zero address, which could lead to an invalid host.

Recommended Mitigation:

Update the changeHost function by implementing:

1. Either require statement checking for a zero address.

   function changeHost(address _newHost) external onlyHost {

   require(_newHost != address(0), "Invalid address");

   if(!participant[_newHost]) {

   revert OnlyParticipantsCanBeHost();

   }

   host = _newHost;

   emit NewHost(host);

   }

2. Or, an ifstatement along with a custom error of ZeroAddress.