Security researcher Jordi Chancel discovered a method to put arbitrary HTML content within <select> elements and place it in arbitrary locations. This can be used to spoof the displayed addressbar, leading to clickjacking and other spoofing attacks. In general this flaw cannot be exploited through email in the Thunderbird and Seamonkey products because scripting is disabled, but is potentially a risk in browser or browser-like contexts. External Reference: http://www.mozilla.org/security/announce/2013/mfsa2013-94.html Acknowledgements: Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Jordi Chancel as the original reporter. Statement: This issue does not affect the version of firefox and thunderbird as shipped with Red Hat Enterprise Linux 5 and 6