The remote Fedora host is missing one or more security updates.
Update to new upstream Thunderbird version 3.1.1, fixing multiple security issues detailed in the upstream advisories: http://www.mozilla.org/security/announce/ Update also includes sunbird package rebuilt against new version of Thunderbird. Note that Tenable Network Security has extracted the preceding description block directly from the Fedora security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.
Update the affected sunbird and / or thunderbird packages.