Vulnerability Instance

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.