
RC4 is leaving Kerberos for good. Here is what breaks and how to migrate in July 2026
Microsoft removes RC4 from Kerberos in staged updates tied to CVE-2026-20833, ending with a July 2026 patch that leaves no rollback. A practical guide for AD and SOC teams: what breaks, how to find RC4 via events 4768/4769 and MDI ready-to-run KQL and migrating to AES in time.





















