After less than 12 hours from when Netscape 8.0 was released, no less than 3 bugs were found in the software. An update, tagged as 8.0.1, has been released, without which users visiting sites rendered with the Gecko engine could be at risk. Details of the fixes in 8.0.1 can be found here, those being:
MFSA 2005-44 Privilege escalation via non-DOM property overrides
Both Netscape and Techspot (us!) recommend that you upgrade to the latest version of the software in order to avoid any potential exploits which these flaws could result in.