http://blogs.pcmag.com/securitywatch...s_reported.php
Version 3.0.1 of iCal, running on the Mac OS X 10.5.1 platform, vulnerable to remote compromise according to Core Security Technologies.
The three attacks are all based on improper checking of data in .ics files, according to
the advisory from Core. The user needs to be convinced to import a malicious file at which point the program can crash or, potentially, arbitrary code be executed in the context of the logged-in user. It may also be possible to compromise iCal clients through a CalDav server.
iCal is a calendar program provided with Mac OS X, It can be used as a standalone program or as a client to a CalDav server.
So far there are no reports of the vulnerability being exploited in the wild.