Microsoft Servers Hit by April Patch Causing Domain Controller Reboot Loops

Microsoft has issued a warning that recent April security updates have caused critical Windows domain controllers to enter persistent reboot loops. This issue primarily affects servers acting as domain controllers, which are essential for managing user access and network resources in Windows environments. The unexpected restarts can lead to significant downtime and operational disruption for organizations relying on these services.

BleepingComputer reports that the problematic patches are linked to the April 2026 security updates. While Microsoft is investigating, the immediate impact is a loss of critical infrastructure availability. Defenders must be prepared to troubleshoot and potentially roll back these updates if their domain controllers exhibit this behavior. The calculus for attackers here is simple: if they can exploit vulnerabilities that lead to instability or denial of service, even indirectly through faulty patches, they can disrupt target operations.