Windows 11の月例更新プログラムKB5074109、KB5073455が公開 - 2026年1月の月例更新、セキュアブートの改良など

2026年1月14日

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Microsoftは1月13日(現地時間)、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 11 Version 25H2/24H2用の累積アップデートKB5074109とWindows 11 Version 23H2用の累積アップデートKB5073455をリリースしました。

更新プログラムは主にシステムの品質を改善し、セキュリティ問題を修正するものです。

自動的にインストールされますが、Windows UpdateまたはMicrosoft Update Catalogを利用して手動でインストールすることもできます。

それぞれの変更点は以下の通りです(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)。

January 13, 2026—KB5074109 (OS Builds 26200.7623 and 26100.7623)

Windows 11 Version 25H2/24H2用の更新プログラムKB5074109では、12月9日に公開されたKB5072033の内容に加え、一部の古いモデムドライバーの削除や、WSLのミラーネットワークが「No route to host」になる問題の修正、NPU搭載デバイスがアイドル時にスリープせず電源が入りっぱなしになる問題の修正が行われています。また、更新プログラムに「新しいSecure Boot証明書を自動配布するためのデバイス判定データ」を含まれるようにする改良も行われています。

リリースノートは以下の通りです。

改良と修正

[Compatibility] This update removes the following modem drivers: agrsm64.sys (x64), agrsm.sys (x86), smserl64.sys (x64) and smserial.sys (x86). Modem hardware dependent on these specific drivers will no longer work in Windows.

[Networking (known issues)]

Fixed: This update addresses an issue where mirrored networking in Windows Subsystem for Linux (WSL) could fail causing “No route to host” errors and preventing access to corporate resources over VPN connections, even when the Windows host remained connected. This might occur after installing KB5067036.

Fixed: This update addresses an issue where you might experience RemoteApp connection failures in Azure Virtual Desktop environments. This might occur after installing KB5070311.

[Power & Battery] Fixed: This update addresses an issue where devices with a Neural Processing Unit (NPU) might stay powered on when idle. This could affect power performance.

[Secure Boot] Starting with this update, Windows quality updates include a subset of high confidence device targeting data that identifies devices eligible to automatically receive new Secure Boot certificates. Devices will receive the new certificates only after demonstrating sufficient successful update signals, ensuring a safe and phased deployment.

[Windows Deployment Services (WDS)] This update introduces a change in behavior in which WDS will stop supporting hands-free deployment functionality by default. Detailed guidance for IT administrators is available in Windows Deployment Services (WDS) Hands‑Free Deployment Hardening Guidance .

[WinSqlite3.dll] Fixed: The Windows core component, WinSqlite3.dll, has been updated. Previously, some security software might have detected this component as vulnerable.

Note: WinSqlite3.dll is a separate component from sqlite3.dll, which is found in application-specific directories and is not a Windows component. If security applications continue to detect sqlite3.dll as vulnerable, contact the developer of the app using sqlite3.dll for an update. If sqlite3.dll is being used by a Microsoft app, install the latest version of the app from the Microsoft Store.

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。

Password icon might be missing or invisible in the lock screen sign-in options

Symptoms

After installing the August 2025 non-security preview update (KB5064081) or later updates, you might notice that the password icon is not visible in the sign-in options on the lock screen. If you hover over the space where the icon should appear, you’ll see that the password button is still available. Select this placeholder to open the password text box and enter your password. After entering your password, you can sign in normally.

Individuals using Windows Home or Pro editions on personal devices are very unlikely to experience this issue. This issue primarily affects enterprise or managed IT environments.

Workaround

This issue is mitigated using Known Issue Rollback (KIR).

For enterprise-managed devices managed by IT departments that have installed the affected update and encountered this issue, IT administrators can resolve it by installing and configuring the Group policy listed below. The special Group Policy can be found in Computer Configuration > Administrative Templates > <Group Policy name listed below>.

For information on deploying and configuring these special Group Policy, please see How to use Group Policy to deploy a Known Issue Rollback.

Group Policy downloads with Group Policy name:

Download for Windows 11 version 24H2, Windows 11 version 25H2: Windows 11 24H2, Windows 11 25H2 and Windows Server 2025 KB5072033 251202_18051 Known Issue Rollback

Important: You will need to install and configure the Group Policy for your version of Windows to resolve this issue. You will also need to restart your device(s) to apply the group policy setting. Note that the Group Policy will temporarily disable the change causing this issue.

We are working on a resolution in a future Windows update and will provide more information when it is available.

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。

January 13, 2026—KB5073455 (OS Build 22631.6491)

Windows 11 Version 23H2用の更新プログラムKB5073455では、12月9日に公開されたKB5071417の内容に加え、古いモデムドライバーの削除や、RDP接続に影響する問題の修正、セキュアブートの改良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

[Compatibility] This update removes the following modem drivers: agrsm64.sys (x64), agrsm.sys (x86), smserl64.sys (x64) and smserial.sys (x86). Modem hardware dependent on these specific drivers will no longer work in Windows.

[Display Kernel] Fixed: This update addresses an issue affecting Remote Desktop Protocol (RDP) connections, where the connection fails and you might need to restart your device.

[Input] Fixed: This update addresses an issue that affects apps such as Outlook, Teams, Edge, Chrome, and Excel. These apps might close unexpectedly when you enter text.

[Secure Boot] Starting with this update, Windows quality updates include a subset of high confidence device targeting data that identifies devices eligible to automatically receive new Secure Boot certificates. Devices will receive the new certificates only after demonstrating sufficient successful update signals, ensuring a safe and phased deployment.

[WinSqlite3.dll] Fixed: The Windows core component, WinSqlite3.dll, has been updated. Previously, some security software might have detected this component as vulnerable.

Note: WinSqlite3.dll is a separate component from sqlite3.dll, which is found in application-specific directories and is not a Windows component. If security applications continue to detect sqlite3.dll as vulnerable, contact the developer of the app using sqlite3.dll for an update. If sqlite3.dll is being used by a Microsoft app, install the latest version of the app from the Microsoft Store.