That's an interesting and worrying point :(

On Fri, 2024-09-27 at 07:19 -1000, Joel Roth via Dng wrote:
> Peter Duffy wrote:
> > My impression so far is that the risk to "leaf nodes" of the
> > internet
> > (ones behind routers provided by ISPs, and including firewalls and
> > NATting) ***should*** be minimal - as UDP port 631 should be
> > blocked by
> > default (if not, the ISP needs kicking), and no one in their right
> > mind
> > would expose it via a port-forwarding hole through the firewall. At
> > least, I can't imagine a valid reason for doing so.
>
> I was considering that many off-the-shelf routers may be running
> CUPS,
> even with no printer connected.
>