Summary
The remote host is missing an update as announced
via advisory SSA:2010-095-01.
Solution
https://secure1.securityspace.com/smysecure/catid.html?in=SSA:2010-095-01
Insight
New mozilla-thunderbird packages are available for Slackware 10.2, 11.0, 12.0, 12.1, 12.2, 13.0, and -current to fix security issues.