MC1388721 — 30-Day Reminder: Final deployment phase for Kerberos RC4 hardening begins with the July 2026 Windows security update

What and WhyWindows updates released in July 2026 will complete the final deployment phase of protections for a Kerberos information disclosure vulnerability (CVE‑2026‑20833). Beginning with this phase, Audit mode is removed, leaving Enforcement mode as the only available option for Kerberos RC4 usage on Windows domain controllers. Environments with remaining RC4 dependencies might experience authentication issues unless those dependencies are remediated or explicitly configured before the July...

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