Fixed a bug where adding custom functions to Object.prototype resulte…

…d with the source of these functions to be outputted in the mail headers. Worse, if the function contained a blank line, the line will be interpreted as the end of the headers zone resulting in some headers being outputted in the mail body (!).

smtp/message.js

@@ -495,8 +495,8 @@ var MessageStream = function(message)
 
       for(var header in self.message.header)
       {
-         // do not output BCC in the headers...
-         if(!(/bcc/i.test(header)))
+         // do not output BCC in the headers (regex) nor custom Object.prototype functions...
+         if(!(/bcc/i.test(header)) && self.message.header.hasOwnProperty (header))
             data = data.concat([fix_header_name_case(header), ": ", self.message.header[header], CRLF]);
       }