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Microsoft Windows 10 KB5066791 cumulative update

Security Patch Release
First reported
Last updated
Happening score
H score 39
1 unique sources, 1 articles

Summary

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Microsoft released Windows 10 KB5066791, the final cumulative update for Windows 10, as the operating system reached end of support on October 14, 2025. The mandatory patch bundles Microsoft's October 2025 Patch Tuesday fixes, including six zero-day vulnerabilities and 172 other flaws. Eligible customers can continue with extended security updates rather than receiving free security fixes.

Related Happenings

Microsoft security patch release for CVE-2026-41091 and CVE-2026-45498

Security Patch Release
First: 21.05.2026 10:49 Last: 21.05.2026 10:49 Sources 1

About this happening: Microsoft rolled out security updates for Defender and related malware protection components to address two zero-days: CVE-2026-41091 and CVE-2026-45498. The fixes cover affected...

Latest development: 21.05.2026 12:52

Microsoft released patches for Microsoft Defender Antimalware Platform version 4.18.26040.7 to address CVE-2026-41091, a link-following privilege-escalation flaw that can let an authorized attacker elevate privileges locally to System, and CVE-2026-45498, a denial-of-service flaw. Microsoft said both vulnerabilities were publicly disclosed and exploited in the wild as zero-days. CISA added both flaws to its Known Exploited Vulnerabilities (KEV) list and urged federal agencies to patch them by June 3.

Microsoft Windows Update restricted-network download failure

Service Disruption
First: 19.05.2026 14:22 Last: 19.05.2026 14:22 Sources 1

About this happening: Microsoft's **Windows Update** is failing in **restricted network environments** after the **January 2026 optional non-security preview updates**, leaving affected systems unable...

Microsoft Windows 11 KB5089549 cumulative update

Security Patch Release
First: 18.05.2026 11:33 Last: 18.05.2026 11:33 Sources 1

About this happening: Microsoft's **KB5089549** **Windows 11** security update is failing to install on some systems, forcing affected devices to roll back during reboot. The problem is tied to a nearl...

Microsoft May 2026 Patch Tuesday release

Security Patch Release
First: 13.05.2026 13:36 Last: 13.05.2026 13:36 Sources 1

About this happening: Microsoft's **May 13, 2026 Patch Tuesday** release fixed **138 vulnerabilities** across its product portfolio, including **Windows**, **Azure**, and **Edge**. None of the flaws we...

Microsoft security patch release for CVE-2026-41089

Security Patch Release
First: 13.05.2026 00:46 Last: 13.05.2026 00:46 Sources 1

About this happening: **Microsoft** and other major software vendors shipped a heavy **May 2026** patch cycle, with fixes spanning **Windows**, **iOS**, **Firefox**, **Oracle** products, and **Chrome**...

Timeline

  1. 14.10.2025 22:07 2 articles · 7mo ago

    Windows 10 KB5066791 final cumulative update released

    Mitigation Patch Update

    Microsoft released the mandatory Windows 10 KB5066791 cumulative update on October 14, 2025 as Windows 10 reached end of support, ending free Windows Update security fixes and technical assistance for the operating system. The release is the final cumulative update for Windows 10, and eligible customers can continue coverage through extended security updates, with consumers able to enroll for up to 1 year and enterprises for up to 3 years.

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  2. 14.10.2025 22:07 1 articles · 7mo ago

    KB5066791 fixes and installation options detailed

    Technical Analysis Update

    The KB5066791 servicing release delivers Microsoft's October 2025 Patch Tuesday fixes, addressing six zero-day vulnerabilities and 172 other flaws, and it updates Windows 10 22H2 to build 19045.6456 and Windows 10 21H2 to build 19044.6456 after installation. The update also fixes PowerShell Remoting and WinRM command timeouts, resolves SMBv1 connectivity problems after KB5065429, addresses a Windows Autopilot Enrollment Status Page issue during OOBE, and can be installed through Windows Update or the Microsoft Update Catalog.

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