The vbd_create function in Xen 3.1.2, when the Linux kernel 2.6.18 on Red Hat Enterprise Linux (RHEL) 5 is used, allows guest OS users to cause a denial of service (host OS panic) via an attempted access to a virtual CD-ROM device through the blkback driver. NOTE: some of these details are obtained from third party information.
https://exchange.xforce.ibmcloud.com/vulnerabilities/64698
http://www.vmware.com/security/advisories/VMSA-2011-0012.html
http://www.securityfocus.com/bid/45795
http://www.securityfocus.com/archive/1/520102/100/0/threaded
http://www.redhat.com/support/errata/RHSA-2011-0017.html