Security issues were identified and fixed in mozilla firefox and
thunderbird:

Mozilla developers and community members identified and fixed several
memory safety bugs in the browser engine used in Firefox 3.6 and
other Mozilla-based products. Some of these bugs showed evidence of
memory corruption under certain circumstances, and we presume that
with enough effort at least some of these could be exploited to run
arbitrary code (CVE-2011-2982).

Security researcher regenrecht reported via TippingPoint's Zero Day
Initiative that a SVG text manipulation routine contained a dangling
pointer vulnerability (CVE-2011-0084).

Mozilla security researcher moz_bug_r_a_4 reported a vulnerability in
event management code that would permit JavaScript to be run in the
wrong context, including that of a different website or potentially
in a chrome-privileged context (CVE-2011-2981).

Security researcher regenrecht reported via TippingPoint's Zero Day
Initiative that appendChild did not correctly account for DOM objects
it operated upon and could be exploited to dereference an invalid
pointer (CVE-2011-2378).

Mozilla security researcher moz_bug_r_a4 reported that web content
could receive chrome privileges if it registered for drop events and a
browser tab element was dropped into the content area (CVE-2011-2984).

Security researcher Mitja Kolsek of Acros Security reported that
ThinkPadSensor::Startup could potentially be exploited to load a
malicious DLL into the running process (CVE-2011-2980).

Security researcher shutdown reported that data from other domains
could be read when RegExp.input was set (CVE-2011-2983).

Packages for 2009.0 are provided as of the Extended Maintenance
Program. Please visit this link to learn more:
http://store.mandriva.com/product_info.php?cPath=149&products_id=490

Additionally, some packages which require so, have been rebuilt and
are being provided as updates.