The child frames in Opera 9 before 9.20 inherit the default charset from the parent window when a charset is not specified in an HTTP Content-Type header or META tag, which allows remote attackers to conduct cross-site scripting (XSS) attacks, as demonstrated using the UTF-7 character set.
osvdb.org/32118
secunia.com/advisories/24312
secunia.com/advisories/25027
www.hardened-php.net/advisory_032007.142.html
www.novell.com/linux/security/advisories/2007_28_opera.html
www.opera.com/support/search/view/855/
www.securityfocus.com/archive/1/461076/100/0/threaded
www.securityfocus.com/bid/22701
www.securitytracker.com/id?1017909
www.vupen.com/english/advisories/2007/0745