Unspecified vulnerability in Opera before 11.00 has unknown impact and attack vectors, related to "a high severity issue."
http://www.opera.com/docs/changelogs/windows/1100/
http://www.opera.com/docs/changelogs/unix/1100/
http://www.opera.com/docs/changelogs/mac/1100/
http://secunia.com/advisories/42653
http://lists.opensuse.org/opensuse-security-announce/2010-12/msg00006.html