Opera before 9.52, when rendering an http page that has loaded an https page into a frame, displays a padlock icon and offers a security information dialog reporting a secure connection, which might allow remote attackers to trick a user into performing unsafe actions on the http page.
https://exchange.xforce.ibmcloud.com/vulnerabilities/44555
http://www.vupen.com/english/advisories/2008/2416
http://www.securitytracker.com/id?1020721
http://www.securityfocus.com/bid/30768
http://www.opera.com/support/search/view/895/
http://www.opera.com/docs/changelogs/windows/952/
http://www.opera.com/docs/changelogs/solaris/952/
http://www.opera.com/docs/changelogs/mac/952/
http://www.opera.com/docs/changelogs/linux/952/
http://www.opera.com/docs/changelogs/freebsd/952/
http://www.openwall.com/lists/oss-security/2008/09/24/4
http://www.openwall.com/lists/oss-security/2008/09/19/2
http://security.gentoo.org/glsa/glsa-200811-01.xml
http://secunia.com/advisories/32538