Mozilla security researcher moz_bug_r_a4 reported a arbitrary code execution attack using a javascript: URL. The Gecko engine features a JavaScript sandbox utility that allows the browser or add-ons to safely execute script in the context of a web page. In certain cases, javascript: URLs are executed in such a sandbox with insufficient context that can allow those scripts to escape from the sandbox and run with elevated privilege. This can lead to arbitrary code execution. Reference: http://www.mozilla.org/security/announce/2012/mfsa2012-56.html
Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges moz_bug_r_a4 as the original reporter of this issue.
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 6 Via RHSA-2012:1089 https://rhn.redhat.com/errata/RHSA-2012-1089.html
This issue has been addressed in following products: Red Hat Enterprise Linux 5 Red Hat Enterprise Linux 6 Via RHSA-2012:1088 https://rhn.redhat.com/errata/RHSA-2012-1088.html