Wire · regulatory
Microsoft's largest Patch Tuesday ever: 622 flaws, Kerberos encryption overhaul
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Fusion42 · 15 July 2026 · Fusion42 review
Microsoft released 570 security patches in July 2026, including 59 critical flaws and three actively exploited zero-days across Windows, Office, Exchange, and Azure. The update also begins mandatory enforcement of Kerberos RC4 encryption phase-out, forcing organisations to upgrade legacy authentication systems.
This Wire brief sits within Fusion42's coverage of Cybersecurity, Cloud Infrastructure and Enterprise Software.
◆ ◆ The Wire takeaway
You now have a hard deadline to rip out legacy Kerberos from your Windows infrastructure—Microsoft isn't asking. If you're running old AD FS or domain controllers on RC4, plan your upgrade path this month or risk being forced into an emergency swap when RC4 stops working.
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1 source · 15 Jul 2026
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