Opera 9.64 allows remote attackers to cause a denial of service (application crash) via an XML document containing a long series of start-tags with no corresponding end-tags. NOTE: it was later reported that 9.52 is also affected.
https://www.exploit-db.com/exploits/8320
https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A5432
https://exchange.xforce.ibmcloud.com/vulnerabilities/49522
http://websecurity.com.ua/3216/
http://lists.opensuse.org/opensuse-security-announce/2009-09/msg00001.html