Here is the official statement from Engineering:
McAfee Firewall Enterprise is not vulnerable to the “TCP Split Handshake” attack. All versions of McAfee Firewall Enterprise protect against this attack, regardless of patch level or configuration. McAfee has confirmed this protection via lab testing using published attack tools, as well as code and architecture review to confirm no similar vulnerability exists.
When successful, the “TCP Split Handshake” attack causes a network security device to allow traffic without applying the configured security policy. Recently, security researchers and some test labs have drawn attention to this attack. The test lab named one firewall vendor (not McAfee Firewall Enterprise) as being not vulnerable to this attack (out of numerous tested). McAfee Firewall Enterprise was not part of the lab testing effort.