Mozilla developers identified and fixed several memory safety bugs in the browser engine used in Firefox 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. Igor Bukanov reported a memory safety problem that was fixed in Firefox 3.6 only.
This is now public: http://www.mozilla.org/security/announce/2010/mfsa2010-74.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-2010:0966 https://rhn.redhat.com/errata/RHSA-2010-0966.html
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2010:0969 https://rhn.redhat.com/errata/RHSA-2010-0969.html