Bad management? Thinking HP wouldn't release and putting people on other tasks in prep for Win 10? Not believing they were critical? Some messed up test or compatibility interaction that ended up slipping the release? Anything else interesting? How long do you think these will go unpatched? If they patch them in a week, will you change your opinion to "wow MS has talent but made a mistake"?

Coming to the conclusion that the world's largest software vendor that ships a rather security enhanced OS (how long did it take OSX to add ASLR), shipped plenty of memory analysis/protection features in their compiler, etc. simply lacks the talent to fix a few bugs... Someone screwed up but it's unlikely to be a technical talent issue. You need to update your priors.

PS: IE kicked ass at the beginning. I was rather excited with it around IE3. And let's not forget they invented XHR. It only totally went south once MS's management thought they'd won and disassembled the team. And hey, MS went from the leader in instant messaging (which could easily have been turned into the dominating social network) to buying Skype and dropping the MSN brand. They know how to drop the ball from a management perspective.