A directory traversal flaw was found in Firefox's resource:// protocol handler. If a user processed malicious content, it could use this flaw to gain access to arbitrary files on the user's system.
This is now public: http://www.mozilla.org/security/announce/2011/mfsa2011-16.html
This issue has been addressed in following products: Red Hat Enterprise Linux 6 Via RHSA-2011:0475 https://rhn.redhat.com/errata/RHSA-2011-0475.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