In response to 0.0.0.0 day, Firefox Nightly version 131 had introduced a new security measure: blocking access to 0.0.0.0/::/::ffff:0.0.0.0 addresses. This change is currently live for Nightly users and will be gradually rolled out to all release users in the near future. Before we implement this ch...
If I were implementing it, I’d just list all interfaces on the machine and see if there’s a service bound to it on the given port. There’s probably only one, but it’s technically undefined behavior I think.