New Update Security Intelligence Updates in Microsoft Defender (Threat Detection Changelog)

[oldschool]

Beta channel update: Engine Version: 1.1.26090.7

 

[oldschool]

Stable channel updates:

• Platform 4.18.26080.4
• Engine 1.1.26080.3

Enhancements and features
Fixed an issue where Windows could incorrectly display a notification stating that “Microsoft Defender Antivirus is turned off” when Windows started or intermittently afterward, even though Defender Antivirus remained active and functioning correctly. For more information, see Incorrect notifications that Microsoft Defender Antivirus is turned off.

Microsoft Defender for Endpoint release notes - Microsoft Defender for Endpoint

 

[oldschool]

Beta channel updates:

• Platform 4.18.26100.3
• Engine 1.1.26100.3

 

[oldschool]

Defender updates:

• Platform 4.18.26090.9
• Engine 1.1.26090.9

Enhancements and features​

• Added automatic protection-engine refresh when the device's resolved license tier changes.
• Fixed a stalled security-intelligence update worker which could block all subsequent updates.
• Addressed an update configuration issue that could leave DisableBmNetworkSensor = 1 after platform updates.
• Renamed the PowerShell configuration-protection property from ControlledConfigurationState to ConfigurationProtection.
• Retained the feature-control cache during signature updates to preserve cached settings through the update lifecycle.
• Improved path-normalization handling for Attack Surface Reduction rules.
• Fixed attack surface reduction exclusions being dropped when multiple policies target the same rule.

Microsoft Defender for Endpoint release notes - Microsoft Defender for Endpoint

Beta channel updates:

• Platform 4.18.26100.4
• Engine 1.1.26100.4

 

[oldschool]

Defender updates October 27, 2026

Platform 4.18.26100.4
Engine 1.1.26100.4

Enhancements and features​

• Reduced CPU usage after full scans by avoiding repeated decompression of Windows image archives (WIM).
• Recognize devices configured using Defender for Endpoint security settings management as managed devices.
• Completed rollout of Microsoft Defender Clipboard Protection- DefenderSessionHelper.exe.