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.
This is now public: http://www.mozilla.org/security/announce/2011/mfsa2011-30.html
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Red Hat Enterprise Linux 5 Via RHSA-2011:1165 https://rhn.redhat.com/errata/RHSA-2011-1165.html
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Via RHSA-2011:1167 https://rhn.redhat.com/errata/RHSA-2011-1167.html
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2011:1166 https://rhn.redhat.com/errata/RHSA-2011-1166.html
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 6 Via RHSA-2011:1164 https://rhn.redhat.com/errata/RHSA-2011-1164.html