The PV domain builder in Xen 4.2 and earlier does not validate the size of the kernel or ramdisk (1) before or (2) after decompression, which allows local guest administrators to cause a denial of service (domain 0 memory consumption) via a crafted (a) kernel or (b) ramdisk.
http://lists.fedoraproject.org/pipermail/package-announce/2012-November/091832.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-November/091844.html
http://lists.fedoraproject.org/pipermail/package-announce/2012-November/092050.html
http://lists.opensuse.org/opensuse-security-announce/2012-11/msg00008.html
http://lists.opensuse.org/opensuse-security-announce/2012-11/msg00009.html
http://lists.opensuse.org/opensuse-security-announce/2012-11/msg00017.html
http://lists.opensuse.org/opensuse-security-announce/2012-11/msg00018.html
http://lists.opensuse.org/opensuse-security-announce/2014-03/msg00015.html
http://lists.opensuse.org/opensuse-security-announce/2014-03/msg00021.html
http://lists.opensuse.org/opensuse-security-announce/2014-04/msg00000.html
http://rhn.redhat.com/errata/RHSA-2013-0241.html
http://secunia.com/advisories/51071
http://secunia.com/advisories/51324
http://secunia.com/advisories/51352
http://secunia.com/advisories/51413
https://exchange.xforce.ibmcloud.com/vulnerabilities/79617
http://www.debian.org/security/2013/dsa-2636