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Today in Microsoft Defender

Every tracked change across Microsoft Defender documentation, in plain English. Browse the archive from 1 January 2026 → About this project →

Day in brief

AKS Deny policies can block Defender for Cloud Security Gating provisioning

The most consequential update adds explicit Defender for Cloud guidance for AKS clusters: Deny policies can trigger RequestDisallowedByPolicy during Security Gating provisioning, even when clusters are compliant. The period also records an Endpoint Linux release, revised Sentinel residency guidance, Vulnerability Management detection and recommendation fixes, and four GA sensor entries.

  • The enablement guide now states that Deny policies targeting AKS managed clusters can cause RequestDisallowedByPolicy when Security Gating provisions resources, including on compliant clusters. It adds steps to identify the blocking assignment in the Activity Log and use Audit or a narrowly scoped exemption with the Azure Policy administrator.

  • The October 2026 release notes list Linux version 101.26091.0004, Azure Linux 4 support, and TCP socket bind telemetry. After gradual rollout, the telemetry will be available in Advanced Hunting through the DeviceNetworkEvents table.

  • The page now states that Sentinel processes and stores processed and configuration data in onboarding destination regions or applicable existing Defender XDR regions. It also expands the processed-data examples and removes the 21Vianet retirement notice.

  • The Fixed Reported Inaccuracies page now lists detection and recommendation fixes, revised Python end-of-support details, and MDVM support for Intel Endpoint Management Assistant and several Microsoft extensions, with entries dated September 7–23 and October 3–9, 2026. Reports and recommendations may change for affected products and vulnerabilities.

  • The changelog adds October 2026 GA entries for sensor versions 0.11.9, 0.10.12, 0.9.70, and 0.8.63. Their images remove trust in affected certificate authorities; review these releases when planning sensor updates.

This period briefing was generated by AI from the tracked Microsoft Learn and Message Center changes.

8 updates

1

Onboard Isoc Workspace

Doc update

The documentation now states that an ISOC workspace follows the same data residency and retention behavior as an Azure Log Analytics workspace and links to related Microsoft Sentinel and Log Analytics guidance.

1
1

Microsoft Defender Endpoint Releases

Feature update

The October 2026 Linux release notes now list version 101.26091.0004, support for Azure Linux 4, and TCP socket bind telemetry. After gradual rollout, the telemetry will be available in Advanced Hunting through the DeviceNetworkEvents table.

1

Enablement Guide Runtime Gated

Feature updateAction required

The guide now explains that `Deny` policies targeting AKS managed clusters can prevent Security Gating provisioning with `RequestDisallowedByPolicy`, even for compliant clusters. It adds steps to identify the blocking assignment in the Activity Log and use `Audit` or a narrowly scoped exemption.

1

Defender Sensor Change Log

Feature update

The changelog adds October 2026 GA entries for sensor versions 0.11.9, 0.10.12, 0.9.70, and 0.8.63. Their images remove trust in affected certificate authorities.

1

Defender For Containers Troubleshoot

Doc updateAction required

The page now explains missing admission-controller resources, how to diagnose failed AKS writes with RequestDisallowedByPolicy, which policies may conflict, and how to resolve the issue through narrowly scoped changes or Microsoft Support.

1

Geographical Availability Data Residency

Feature update

The page now states that Sentinel will process and store processed and configuration data in the onboarding destination regions or applicable existing Defender XDR regions. It also adds cases to the processed-data examples and removes the 21Vianet retirement notice.

1

Fixed Reported Inaccuracies

Feature update

The page now lists detection and recommendation fixes, updated Python end-of-support details, and MDVM support for Intel Endpoint Management Assistant and several Microsoft extensions, dated September 7–23 and October 3–9, 2026.