An unusual oversight in how OS X's Spotlight feature handles privacy settings in Apple Mail leaves the door open to spammers, phishers and online tracking companies who can obtain private data such as your IP address, current operating system version, browser details and more, whenever an email message is previewed in Spotlight.
First discovered by German technology news site Heise, the bug takes advantage of a common information harvesting technique and a Mail setting which determines whether or not the program loads remote content in emails.