Microsoftは本日、毎月米国時間の第2火曜日に提供している月例更新の一環として、Windows 10の各バージョンに対する累積アップデートをそれぞれ公開しました。Windows 10 Version 20H2/21H1/21H2/22H2: KB5126657Windows 10 Version 1909: EOSWindows 10 Version 1903: EOSWindows 10 Version 1809: KB5126657Windows 10 version 1803: EOSWindows 10 version 1709: EOSWindows 10 version 1703: EOSWindows 10 version 1607: KB5126657Windows 10 Version 1511: EOSWindows 10 Version 1507: EOSそれぞれWindows UpdateまたはMicrosoft Update Catalogを利用して導入することが可能で、変更点は以下の通りです(セキュリティアップデートの内容は日本Microsoftのブログで参照できます)。October 13, 2026—KB5126657 (OS Builds 19045.7807 and 19044.7807)Windows 10 Version 22H2/21H2用の更新プログラムKB5126657では、タイムゾーン関連の変更や、ReFSのセキュリティ強化、ファイル履歴の修正などが行われています。リリースノートは以下の通りです。改良と修正[Time and Date]This update enables permanent Daylight Savings Time (DST) support for British Columbia and Alberta starting in November 2026.This update introduces the new time zone Manitoba Standard Time "(UTC-5:00) Manitoba".[ReFS security] This update adds auditing and optional policy controls for ReFS volumes on externally attached storage devices. Auditing is enabled by default, while enforcement controls remain disabled by default to give administrators time to evaluate and prepare for future security hardening changes. To learn more, see KB5130741.[Storage Spaces] Addresses an issue that might cause some Storage Spaces Direct virtual disks to remain offline after installing a Windows update. This issue occurs when valid tiered storage metadata is incorrectly identified as invalid during recovery, preventing affected virtual disks and dependent workloads from coming online.[File History (known issue)] Fixed: This update addresses an issue where File History might fail to back up or restore files to an external drive or network location. Affected devices might incorrectly display a "Reconnect your drive" message even when a compatible backup drive is connected and working properly.[Secure Boot] This update continues the deployment of updated Secure Boot certificates using the latest high-confidence targeting data to identify eligible devices that are ready to automatically receive the new certificates. Deployment through Windows Update remains ongoing across supported device.既知の不具合更新プログラムには以下の1件の既知の不具合が存在します。USB Audio Class 1.0 devices with error Code 10 or no outputSymptomsAfter installing the September 8, 2026, Windows security update, some USB Audio Class 1.0 devices might fail to start or produce audio. Affected devices might experience one or more of the following symptoms:The device displays an error in Device Manager: "This device cannot start (Code 10).”No audio output.Volume controls are unresponsive or remain at zero.Sound settings are unresponsive or unavailable.Some devices might function in standard stereo configurations but fail when using multichannel audio features, including 8-channel or 3D audio modes. Some customers have reported that they're able to restore audio in these cases by switching to 2-channel mode.This issue is limited to USB Audio Class 1.0 devices.ResolutionThis issue is partially resolved in the out-of-band (OOB) update released on September 14, 2026. This OOB update resolves the symptoms experienced on devices using 8-channel or 3D audio modes. Microsoft is working to address the other symptoms and will provide more information when it is available.IT administrators who need an immediate workaround for the symptoms not addressed yet by the OOB update should contact Microsoft Support for Business for assistance.更新プログラムはWindows Updateの他、Microsoft Update Catalog、Windows Server Update Services(WSUS)を利用してインストールすることができます。