The SSL functionality in Cisco NX-OS on the Nexus 1000V does not properly verify X.509 certificates, which allows man-in-the-middle attackers to spoof servers, and intercept or modify Virtual Supervisor Module (VSM) to VMware vCenter communication, via a crafted certificate, aka Bug ID CSCud14837.
http://tools.cisco.com/security/center/content/CiscoSecurityNotice/CVE-2013-1212