VMware recently released Security Advisorty VMSA-2013-0011 addressing an NFC protocol vulnerability affecting ESXi and EXI (CVE-2013-1661.)  Details are available at https://www.vmware.com/support/support-resources/advisories/VMSA-2013-0011.html

The NFC (Near Field Communication) Protocol is used in tap-to-pay cards and sharing contacts between mobile devices.  This vulnerability exposes the hypervisor to a denial-of-service.

UPDATE: NFC in this case refers to Network File Copy.  Which makes a lot more sense, I was wondering how you'd tap two VMs together. Thank you sine nomine.