VMware ESXi 4.0 through 5.1 and ESX 4.0 and 4.1 allow remote attackers to cause a denial of service (NULL pointer dereference) by intercepting and modifying Network File Copy (NFC) traffic.
https://exchange.xforce.ibmcloud.com/vulnerabilities/90559
http://www.vmware.com/security/advisories/VMSA-2014-0001.html
http://www.securitytracker.com/id/1029643
http://www.securityfocus.com/bid/64995