Unchecked_Call_Return_Value.md

Unchecked Call Return Value

The return value of a message call is not checked. Execution will resume even if the called contract throws an exception. If the call fails accidentally or an attacker forces the call to fail, this may cause unexpected behaviour in the subsequent program logic.

contract MyConc{
    function my_func(address payable dst) public payable{
        dst.call.value(msg.value)("");
    }
}

The return value of the low-level call is not checked, so if the call fails, the Ether will be locked in the contract. If the low level is used to prevent blocking operations, consider logging failed calls.

Recommendation

Ensure that the return value of a low-level call is checked or logged.

contract MyConc{
      function my_func(address payable dst) public payable{
          (bool success, )=dst.call.value(msg.value)("");
          require(success, "transaction failed");
      }
  }