Opera before 9.52 does not check the CRL override upon encountering a certificate that lacks a CRL, which has unknown impact and attack vectors. NOTE: it is not clear whether this is a vulnerability, but the vendor included it in a security section of the advisory.
https://exchange.xforce.ibmcloud.com/vulnerabilities/45589
http://www.vupen.com/english/advisories/2008/2416
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
http://secunia.com/advisories/31549
http://my.opera.com/yngve/blog/2008/06/27/nobody-checks-the-padlock-debunked-by-opera-users
http://my.opera.com/community/forums/topic.dml?id=241988&t=1222404671&page=1