Opera 7.54 and earlier uses kfmclient exec to handle unknown MIME types, which allows remote attackers to execute arbitrary code via a shortcut or launcher that contains an Exec entry.
https://exchange.xforce.ibmcloud.com/vulnerabilities/18457
http://www.zone-h.org/advisories/read/id=6503
http://www.gentoo.org/security/en/glsa/glsa-200502-17.xml
http://lists.suse.com/archive/suse-security-announce/2005-Mar/0007.html