"The other restrictions that had already been identified by Qualys ... are, Cisco says, quite unlikely in any real-world application."
Yeah I'm sure a hacker wouldn't dream of making up a hostname that fit those restrictions.
Reminds me of the time I was re-educating a developer on SQL injection, and asked him what would happen if there was a quote in a user-supplier input:
"Chances are less"
... sigh ...