Windows 11 KB5124008 update breaks domain trust for some users
Microsoft is investigating Windows 11 KB5124008 breaking Active Directory domain trust, leaving some users unable to log in with valid credentials.
Administrators report the Windows 11 KB5124008 security update breaks the secure channel between domain-joined machines and Active Directory, causing login failures on Windows 11 25H2 systems after reboot. The failures are linked to the Machine Identity Isolation feature, which in enforcement mode moves machine account secrets into Credential Guard and removes the LSA copy; one admin saw 11 of roughly 256 devices affected. Workarounds include setting MachineIdentityIsolation to 0 and repairing the secure channel with Test-ComputerSecureChannel, though Microsoft has confirmed no root cause or official fix and warns disabling the feature can also break domain authentication.
CVE-2026-50522: Microsoft SharePoint Server RCE Vulnerability
CVE-2026-50522 is an unauthenticated .NET deserialization RCE in SharePoint Server Subscription, 2019, and 2016; Microsoft patched it July 14, 2026.
CVE-2026-50522 (CWE-502) lets unauthenticated attackers send crafted serialized .NET payloads to network-accessible SharePoint endpoints, triggering gadget-chain deserialization and remote code execution under the privileged SharePoint service account. It affects SharePoint Server Subscription Edition, SharePoint Server 2019, and SharePoint Server 2016 Enterprise; Microsoft published the advisory on July 14, 2026. The EPSS score is 20.346%, but no public PoC exists and the flaw is not in CISA's KEV catalog at publication. Mitigations include applying Microsoft updates, rotating SharePoint machine keys, enabling AMSI, and restricting internet exposure.