The postmortem on this will be interesting. A few days prior Microsoft said several versions of on premise Exchange are permanently vulnerable.

Maybe AI scanning found these Exchange exploits and after laying off so many developers, they vibe coded an exploit fix and deployed it. But behind the scenes it is all just still Exchange which if anyone has experience managing, its a complex nightmare of code going back decades. With all sorts of Active Directory requirements and everything else. The mail database system it uses, and probably still used in Office 365 (Office 363 today?) is also a nightmare.

Just speculation though