A use after free flaw was found in the way Firefox appended frame and iframe elements to a DOM tree when the NoScript add-on was enabled. If a user processes malicious HTML content it could result in arbitrary code execution with the permissions of the user.
This is public via: http://www.mozilla.org/security/announce/2011/mfsa2011-12.html
This issue has been addressed in following products: Red Hat Enterprise Linux 4 Via RHSA-2011:0473 https://rhn.redhat.com/errata/RHSA-2011-0473.html
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 4 Via RHSA-2011:0471 https://rhn.redhat.com/errata/RHSA-2011-0471.html