Microsoft Releases Critical Security Update KB5122878 for Windows 10

On September 8, 2026, Microsoft released the Windows 10 KB5122878 extended security update, addressing a record 966 vulnerabilities, including two actively exploited zero-day flaws. This update is crucial for users of Windows 10 Enterprise LTSC and those enrolled in the Extended Security Update (ESU) program. The update primarily focuses on security enhancements and bug fixes, with notable improvements in Secure Boot, OMA DM protocol logging, and Windows Code Integrity policies. Users are advised to check for updates manually through Windows Update to ensure their systems are protected. The update also adjusts Morocco Standard Time due to a policy change effective September 20, 2026. The cumulative update raises concerns due to the high number of vulnerabilities patched, emphasizing the need for immediate action by system administrators.

Key Points: • Microsoft's KB5122878 update addresses 966 vulnerabilities, including two zero-day flaws. • Users of Windows 10 Enterprise LTSC and ESU program must install this update promptly. • The update includes critical enhancements to Secure Boot and Windows Code Integrity policies.