Resolved after 1 hour 22 minutes, affecting Control Edge and Invoice Manager and 1 more, on May 6, 2026.
Based on the following Notification from Microsoft: Warning Windows updates for CVE-2026-20833 enforce RC4 hardening in phases. Plan and complete remediation before full enforcement: * January 13, 2026 - Initial deployment phase:Updates introduce audit signals and preparation controls. * April 2026 - Enforcement phase \(manual rollback available\):Default Kerberos KDC behavior shifts to AES-first, and RC4-dependent scenarios can start failing unless explicitly configured. * July 2026 - Enforcement phase \(final\):Updates remove rollback support and keep enforcement enabled. we disabled the Kerberos RC4 encryption on the EntraID Domain Services. The configuration was leading to the mentioned incident. As this will be anyhow eminent to happen \( enforcement of Kerberos to AES \) we will continue internal investigation with Microsoft Support to identify root cause of the action applied today. Until further notice the Kerberos RC4 encryption will remain enabled.
Affected components
Update timeline
- investigating May 06, 2026, 09:01 AM UTC
We are currently investigating this issue.
- investigating May 06, 2026, 09:02 AM UTC
We are continuing to investigate this issue.
- monitoring May 06, 2026, 09:45 AM UTC
A fix has been implemented and we are monitoring the results.
- monitoring May 06, 2026, 10:23 AM UTC
We are continuing to monitor for any further issues.
- resolved May 06, 2026, 10:23 AM UTC
This incident has been resolved.
- postmortem May 06, 2026, 10:24 AM UTC
Based on the following Notification from Microsoft: Warning Windows updates for CVE-2026-20833 enforce RC4 hardening in phases. Plan and complete remediation before full enforcement: * January 13, 2026 - Initial deployment phase:Updates introduce audit signals and preparation controls. * April 2026 - Enforcement phase \(manual rollback available\):Default Kerberos KDC behavior shifts to AES-first, and RC4-dependent scenarios can start failing unless explicitly configured. * July 2026 - Enforcement phase \(final\):Updates remove rollback support and keep enforcement enabled. we disabled the Kerberos RC4 encryption on the EntraID Domain Services. The configuration was leading to the mentioned incident. As this will be anyhow eminent to happen \( enforcement of Kerberos to AES \) we will continue internal investigation with Microsoft Support to identify root cause of the action applied today. Until further notice the Kerberos RC4 encryption will remain enabled.
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