So put two and two and the vulnerability requires the presence of an installed modem. Not a network chipset. A fucking modem chipset or an external modem hooked up thru serial or USB.
The last PC that I used which also had an onboard modem was back in 2003. We stopped using dialup later that year and switched entirely to DSL.
Whatever. Somebody more knowledgeable about this looks hard at more specialized PCs that still use modems are likely to be brought down using this vulnerability.