In the PWN2OWN contest at the 2008 CanSecWest security conference in Vancouver, British Columbia, an exploit of Safari caused Mac OS X to be the first OS to fall in a hacking competition. Participants competed to find a way to read the contents of a file located on the user's desktop in one of three operating systems: Mac OS X Leopard, Windows Vista SP1, and Ubuntu 7.10. On the second day of the contest, when users were allowed to physically interact with the computers (the prior day permitted only network attacks), Charlie Miller compromised Mac OS X through an unpatched vulnerability of the PCRE library used by Safari. Miller was aware of the flaw before the conference and worked to exploit it unannounced, as is the common approach in these contests. The exploited vulnerability and other flaws were patched in Safari 3.1.1.