Ouch. Poor old Microsoft. https://www.zdnet.com/article/google-discloses-windows-zero-day-exploited-in-the-wild
@lightweight To be fair, Microsoft isn't unlike other companies in this regard. Most of the software in the world is overly complex and hard to maintain. OTOH, Microsoft has added extra complexity in anticompete measures, and its closed source nature makes for less opportunities for refactoring and less avenues to improvement.
Like most capitalistic software companies, quality and security come second to cost and marketing concerns (and corporate ego massaging).