XBL bindings accessible via improper CSS declarations — Mozilla

Security researcher Cody Crews reported a method to trigger chrome level XML Binding Language (XBL) bindings through web content. This was possible because some chrome accessible CSS stylesheets had their primary namespace improperly declared. When this occurred, it was possible to use these stylesheets to manipulate XBL bindings, allowing web content to bypass security restrictions. This issue was limited to a specific set of stylesheets.