2015/05/13 - 5:20 AM PDT
We are aware of the QEMU security issue assigned CVE-2015-3456, also known as "VENOM," which impacts various virtualized platforms. There is no risk to AWS customer data or instances.
Information on the Xen-specific advisory can be found below:
Xen Security Advisory 133 (CVE-2015-3456) - Privilege escalation via emulated floppy disk drive http://xenbits.xen.org/xsa/advisory-133.html