Courtesy of Derek at another security site:
Quote from: Derek
QuoteApple's Safari browser is vulnerable to an attack that allows a malicious web site to read files on a user's hard drive without user intervention. This can be used to gain access to sensitive information stored on the user's computer, such as emails, passwords, or cookies that could be used to gain access to the user's accounts on some web sites. The vulnerability has been acknowledged by Apple.
http://brian.mastenbrook.net/display/27
http://www.theregister.co.uk/2009/01/13/safari_data_snooping_bug/