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Microsoft Releases Windows 11 September 2026 Patch Tuesday Updates

· Original article ↗

Summary

Microsoft released mandatory Windows 11 updates KB5124008 and KB5122880 for versions 25H2/24H2 and 23H2, saying they address 1,000 vulnerabilities and include feature and reliability improvements.

Key points

  • KB5124008 and KB5122880 are mandatory cumulative updates for Windows 11 versions 25H2/24H2 and 23H2.
  • Microsoft says the September 2026 Patch Tuesday updates address 1,000 vulnerabilities; the article does not identify them individually.
  • Administrator Protection, which is off by default, enables just-in-time administrative privileges and is intended to harden against elevation-of-privilege attacks; Microsoft says it is not a formal security boundary.
  • The release adds process isolation for Microsoft Execution Containers, with policies to restrict access to resources such as files, networking, and the user interface.
  • A preview capability lets authorized components tag agentic processes and passes the identifier to child processes and, during authentication, to Web Account Manager.
  • The updates also introduce taskbar and Start menu customization, Windows Search changes, and reliability improvements.

Article Details

Event Type
Microsoft released mandatory September 2026 Patch Tuesday cumulative updates for Windows 11 versions 25H2/24H2 and 23H2.
Impact
The updates address 1,000 vulnerabilities and bugs and add Windows 11 features and reliability improvements, including Administrator protection and process isolation for Microsoft Execution Containers. The article reports no known new issues.

Vendors

MicrosoftMicrosoft has released Windows 11 KB5124008 and KB5122880 as mandatory cumulative updates for 25H2/24H2 and 23H2, delivering September 2026 Patch Tuesday fixes for 1,000 vulnerabilities along with bug fixes and new

Products

Microsoft Execution ContainersThis update introduces Process Isolation for Microsoft Execution Containers (MXC), a fast, lightweight boundary for responsive workloads such as coding agents and model-generated code.Microsoft IntuneThis feature is turned off by default and can be enabled using OMA-URI in Microsoft Intune or through Group Policy.Windows 11Microsoft has released Windows 11 KB5124008 and KB5122880 as mandatory cumulative updates for 25H2/24H2 and 23H2, delivering September 2026 Patch Tuesday fixes for 1,000 vulnerabilities along with bug fixes and new

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