It’s good this security issue was fixed, but the probability that it would be exploited was less than tiny, even on public WiFi networks.
It’s addressed now. Move along and stop worrying.
It’s indicative of extremely poor coding practices at apple. The fact this made it through code reviews (which we hope are being performed!) is not a good indicator of the quality of product they are releasing nor their development practices. Most major bugs start with something trivial like this that is overlooked.