Multiple HVM control operations in Xen 3.4 through 4.2 allow local HVM guest OS administrators to cause a denial of service (physical CPU consumption) via a large input.
http://lists.opensuse.org/opensuse-security-announce/2012-12/msg00001.html
http://lists.opensuse.org/opensuse-security-announce/2014-03/msg00021.html
http://secunia.com/advisories/51397
http://secunia.com/advisories/51486
http://secunia.com/advisories/51487
http://secunia.com/advisories/55082
http://security.gentoo.org/glsa/glsa-201309-24.xml
https://exchange.xforce.ibmcloud.com/vulnerabilities/80484