Depends on the hack but the majority seem to be from parsers for various formats, from images, to unicode and text data etc... A message has to be able to disp

Depends on the hack but the majority seem to be from parsers for various formats, from images, to unicode and text data etc... A message has to be able to display so many different types of content. A flaw in any one of those could be exploited. Combine a bunch of flaws together and you suddenly can do quite a bit.