Opera before 11.50 allows remote attackers to cause a denial of service (disk consumption) via invalid URLs that trigger creation of error pages.
https://exchange.xforce.ibmcloud.com/vulnerabilities/68323
http://www.securityfocus.com/bid/48501
http://www.opera.com/support/kb/view/996/
http://www.opera.com/docs/changelogs/windows/1150/
http://www.opera.com/docs/changelogs/unix/1150/
http://www.opera.com/docs/changelogs/mac/1150/
http://secunia.com/advisories/45060