Apple has released Safari 5.0 has been released, it addresses several key security issues including use after free issue related to PDF files and design flaws which can aid in phishing attacks. Apple has also address various issues in WebKit including handling of local storage which can lead to creation of database files to be created outside the designated directory, user after free issue related to HTML buttons, style sheet HREF redirection resulting in lost of sensitive data and many of the ZeroDay Initiative submissions from wushi from team 509. For a complete list users and administrators use follow the references provided.
This update is critical and requires a reboot, user should install the update immediately.