Kielhofner has posted a test page that allows system admins to test to see if their equipment is vulnerable.
As news of this issue spreads further some controllers are affected and some aren't. That's more or less what I expected. Here's what I know about fixing this.
It has been my understanding that Intel provides at least two EEPROM versions for this chip: one with BMC enabled and one without. My controllers do not have BMC enabled, therefore my fix only applies to non-BMC enabled controllers. This is unfortunate because the BMC enabled controllers seem to be much more widely used. Even with that other than the very basics (MAC address and checksum) I don't know the meaning of these values. Another reason not to reprogram the EEPROM on your NIC based on what some guy on the internet told you.
With that being said here is a diff between an affected EEPROM and a good EEPROM: