"0-day ... still not fixed" makes it sound like someone is expecting Microsoft to have created a patch for a new exploit with same day turnaround. And therefore what's the big deal that they haven't?
If you want to use the "day" framing, the appropriate headline is "90-day exploit still not fixed". The entire point is that it's an old exploit that is still unpatched, and not some new discovery.
0-day versus "publicly disclosed unpatched vulnerability" doesnt help anyway