Putting his money where his mouth is, so to speak, security reseacher Charlie Miller exploited Safari in mere seconds to take control of a test MacBook in the Pwn2Own contest held during the CanSecWest security conference. In fact, he did so with a default configuration and all security updates applied. Microsoft's Internet Explorer 8 and Mozilla's Firefox 3 were also successfully exploited later in the afternoon.
Read more here: Safari successfully exploited in seconds in Pwn2Own contest - Ars Technica