That CVE only shows how to factory-reset a single MyBook to which you can connect and send HTTP requests. There's still something missing to explain how it could happen to seemingly all MyBook's at once, including those behind a NAT.
> explain how it could happen to seemingly all MyBook's at once
Explain what makes you think this happened to all of them at once. That's a huge leap
There are comments in this thread from people who read about this in the news, checked their own device, and found it was wiped as well. This seems like it would be very unlikely to happen if this were just happening in isolated cases.
Now you're just advocating for the Hasty Generalization Fallacy