CyberNew CyberNew
Defensive Security & Blue Team BleepingComputer 1 month ago

Windows 11 cumulative updates KB5124008 & KB5122880 released

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CyberNew Threat Research Desk
• Original Reporting: BleepingComputer
CyberNew Threat Intel Assessment
Assessed Severity: MEDIUM
Impacted Surface
Client Endpoints & Operating Systems
Intelligence Sector
Defensive Security & Blue Team

Analyst Takeaway

"Microsoft has released Windows 11 KB5124008 and KB5122880 cumulative updates for versions 25H2/24H2 and 23H2 to fix security vulnerabilities, bugs, and add new features. Today's updates are mandatory as they contain the September 2026 Patch Tuesday security patches for 1,000 vulnerabilities discovered in previous months. You can install today's update by going to Start > Settings > Windows Update..."

Recommended Defense & Mitigation

  • Threat Monitoring: Ingest published IOCs into SIEM/EDR detection rules for continuous telemetry monitoring.
  • Security Awareness: Alert staff and maintain baseline endpoint hardening across endpoints.
Curated & Verified by CyberNew Threat Intelligence Desk Standard Defense Framework (NIST / MITRE ATT&CK)

Windows 11

Microsoft has released Windows 11 KB5124008 and KB5122880 cumulative updates for versions 25H2/24H2 and 23H2 to fix security vulnerabilities, bugs, and add new features.

Today's updates are mandatory as they contain the September 2026 Patch Tuesday security patches for 1,000 vulnerabilities discovered in previous months.

You can install today's update by going to Start > Settings > Windows Update and clicking on 'Check for Updates.'

You can also manually download and install the update from the Microsoft Update Catalog.

This is the ninth 'Patch Tuesday' release in 2026, and it's based on 24H2, which means 25H2 gets the same update. There are no exclusive or special changes. You'll get the same fixes across the two versions of Windows 11.

What's new in the September 2026 Patch Tuesday update

With today's update, Microsoft added a movable taskbar, Windows Search without Bing, and more.

Here's the full list of improvements and fixes:

Taskbar

  • This update gives you more ways to customize the taskbar to match how you work and make better use of screen space.

    • New! You can now choose whether the taskbar appears at the bottom, top, left, or right side of your screen. In these other positions, tooltips, flyouts, and animations will still come from the taskbar, and most customization settings, such as never combining taskbar icons, will work with all locations. Search box and smaller taskbar are currently supported only for top and bottom positions. To change the position of the taskbar, go to Settings > Personalization > Taskbar > Taskbar behaviors > Taskbar position

    • New! A smaller taskbar option is now available to help maximize screen space on smaller devices. This experience reduces the size of taskbar icons and the taskbar height while maintaining access to key features such as Start, Search, and the system tray. To change your taskbar size, go to Settings > Personalization > Taskbar > Taskbar behaviors > Taskbar size. When set to Small, both the icons and the taskbar height become smaller.

    • New! The Taskbar behaviors section of the Taskbar settings page is now expanded by default for improved discoverability.

  • This update improves reliability of loading the system tray area of the taskbar for non-touch PCs.

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Source Verification & Original Intelligence

This threat report was reviewed by CyberNew analysts and cross-referenced with primary security disclosures from BleepingComputer.

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