Not just one! (Score 4, Informative)

Although eEyes' reports look a bit confusing (look at the "Vulerability is over" image at the bottom), I think according to this page http://www.eeye.com/html/research/upcoming/index.h tml there are 3 security vulnerabilities affecting IE and Outlook that allow remote code execution.
The oldest one is 60 days old now and still not fixed.