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The Update Bureau

Monthly Patch Briefing

September 2026

66 updates released this month .

Updates, page 2

Updates, page 2:
  • Windows 11 · 26H2
    Windows 11 Windows 11 Insider 26H2 Insider Preview
    Experimental Channel
    Build 26340.9482

    Faster File Explorer search and a red screen-capture border

    The Experimental Channel build tests faster File Explorer search, a red screen-capture border, and other interface changes, plus fixes for context menu, Settings, and brightness issues.

    Changes 1 new · 6 improved · 4 fixes
  • Windows 11 · 25H2
    Windows 11 Windows 11 Insider 25H2 Insider Preview
    Beta Channel
    Build 26220.9472

    Phone-to-PC webpage resume and File Explorer section state

    Beta Channel Insiders get more ways to resume phone webpages on a PC and File Explorer remembers which Home sections they expanded or collapsed. The build also includes Settings fixes and visual changes.

    Changes 4 improved · 2 fixes
  • Windows 11 · 26H1
    Windows 11 26H1 Windows 11 26H1 Security update
    Zero-day Updated
    KB5124012

    An exploited Windows Update Stack flaw is closed

    An actively exploited Windows Update Stack flaw gets a security fix, and Teams and Outlook crashes on Arm64 PCs are addressed. The update also changes Morocco time and improves remote-session audio.

    Build 28000.2954
    Security 640 CVEs 54 critical 1 exploited
    Replaced by KB5129194 →
  • Windows 11 · 24H2, 25H2
    Windows 11 24H2 / 25H2 Windows 11 24H2 / 25H2 Security update
    Zero-day Updated
    KB5124008

    Windows Update flaw exploited; mouse and desktop display fixes

    An actively exploited flaw in the Windows Update stack gets a security fix, alongside fixes for mouse settings, black desktop backgrounds, and app crashes on Arm64 PCs.

    Builds 26100.9445 26200.9445
    Security 642 CVEs 54 critical 1 exploited
    Replaced by KB5129195 →
  • Windows 11 · 23H2
    Windows 11 23H2 Windows 11 23H2 Security update
    Zero-day Updated
    KB5122880

    An exploited Windows Update flaw gets an access fix

    An actively exploited Windows Update flaw could let attackers gain higher access. The update also addresses remote audio problems and adjusts Morocco's time zone.

    Build 22631.7582
    Security 614 CVEs 53 critical 1 exploited
    Replaced by KB5129242 →
  • Windows 11 · Future platforms
    Windows 11 Windows 11 Insider Future platforms Insider Preview
    Experimental Channel
    Build 29661.1000

    IAKerb enabled by default; cursor and update fixes

    Experimental Channel Insiders get IAKerb enabled by default, fixes for mouse cursor and pointer-speed problems, and a fix for Windows Update error 0x80070005.

    Changes 1 improved · 4 fixes
  • Windows 11 · 26H1
    Windows 11 Windows 11 Insider 26H1 Insider Preview
    Experimental Channel
    Build 28120.2912

    Touchpad zoom and portrait-monitor cursor direction fixes

    Fixes touchpad zoom in some apps and incorrect mouse-cursor direction on portrait monitors for Experimental Channel Insiders.

    Changes 2 fixes
  • Windows 11 · 26H1
    Windows 11 Windows 11 Insider 26H1 Insider Preview
    Beta Channel
    Build 28020.2904

    Touchpad zoom works again in some apps

    Includes general improvements and fixes an issue that stopped touchpad zoom from working in certain apps.

    Changes 1 fix
  • Windows 11 · 26H2
    Windows 11 Windows 11 Insider 26H2 Insider Preview
    Experimental Channel
    Build 26340.9354

    Narrator math reading and per-display Magnifier controls

    Experimental Channel Insiders get new Narrator support for reading math and Magnifier controls for separate displays, alongside changes to Settings, audio, and fonts and several fixes.

    Changes 4 new · 21 improved · 4 fixes
  • Windows 11 · 25H2
    Windows 11 Windows 11 Insider 25H2 Insider Preview
    Beta Channel
    Build 26220.9343

    Saved Wi-Fi in recovery and a refreshed AutoPlay dialog

    Updates AutoPlay, adds saved Wi-Fi support in Windows Recovery, and improves personalization and File Explorer. It also includes fixes and known issues.

    Changes 5 new · 15 improved · 4 fixes
  • Windows 10 · 21H2, 22H2
    Windows 10 21H2 / 22H2 Windows 10 21H2 / 22H2 Security update
    Zero-day Updated
    KB5122878

    Windows ALPC flaw under attack; remote audio issue addressed

    An actively exploited Windows ALPC flaw is among the security fixes. The update also addresses Remote Desktop audio and a BitLocker recovery-key issue.

    Builds 19044.7725 19045.7725
    Security 578 CVEs 49 critical 1 exploited
    Replaced by KB5129236 →
  • Windows 10 · 1809
    Windows 10 1809 Windows 10 1809 Security update Also for Windows Server
    Zero-day Updated
    KB5122876

    Exploited ALPC flaw patched; remote-session audio addressed

    Attackers are exploiting a Windows ALPC flaw to gain higher access. Remote-session audio also gets a fix, though some USB audio problems remain.

    Build 17763.9245
    Security 622 CVEs 55 critical 1 exploited
    Replaced by KB5129238 →
  • Windows 10 · 1607
    Windows 10 1607 Windows 10 1607 Security update Also for Windows Server
    Zero-day Updated
    KB5123099

    Windows ALPC flaw under attack; Remote Desktop audio addressed

    Attackers are exploiting a Windows ALPC privilege flaw. The update also addresses Remote Desktop audio problems and adds Secure Boot certificate targeting data.

    Build 14393.9512
    Security 559 CVEs 45 critical 1 exploited
    Replaced by KB5129239 →
  • Windows Server · 2025
    Windows Server 2025 Windows Server 2025 Security update
    Zero-day Updated
    KB5122871

    Windows Update Stack flaw under active attack

    An actively exploited Windows Update Stack flaw is among the security fixes. The update also improves networking, Remote Desktop audio, and Sysmon.

    Build 26100.33438
    Security 690 CVEs 64 critical 1 exploited
    Known issues 1 open
    Replaced by KB5129235 →
  • Windows Server · 2022
    Windows Server 2022 Windows Server 2022 Security update
    Zero-day Updated
    KB5122882

    Exploited ALPC flaw patched; Hyper-V restart issue fixed

    Patches an actively exploited flaw in Windows ALPC and fixes a Hyper-V issue that could unexpectedly restart some virtual machines.

    Build 20348.5622
    Security 651 CVEs 61 critical 1 exploited
    Known issues 1 open
    Replaced by KB5129237 →
  • Windows Server · 2019
    Windows Server 2019 Windows Server 2019 Security update Also for Windows 10
    Zero-day Updated
    KB5122876

    An exploited ALPC flaw is patched; Remote Desktop audio is addressed

    An exploited Windows ALPC flaw is patched, and Remote Desktop audio redirection is addressed for some configurations. USB Audio Class 1.0 devices can still have sound problems.

    Build 17763.9245
    Security 626 CVEs 59 critical 1 exploited
    Replaced by KB5129238 →
  • Windows Server · 2016
    Windows Server 2016 Windows Server 2016 Security update Also for Windows 10
    Zero-day Updated
    KB5123099

    Actively exploited ALPC flaw; Remote Desktop audio addressed

    An actively exploited ALPC flaw could let attackers gain higher privileges. The update also addresses remote-session audio problems, but some USB audio issues remain.

    Build 14393.9512
    Security 563 CVEs 49 critical 1 exploited
    Replaced by KB5129239 →
  • Exchange Server · RTM
    Exchange Server Subscription Edition RTM Exchange Server Subscription Edition RTM Security update
    KB5121608

    Exchange vulnerabilities addressed; published calendar feeds may fail

    Security flaws are addressed, but published calendar feeds and Korean-content processing have known issues.

    Build 15.2.2562.49
    Security 9 CVEs
    Known issues 3 open
    Replaced by KB5129955 →
  • Exchange Server · CU15
    Exchange Server 2019 CU15 Exchange Server 2019 CU15 ESU only Security update
    KB5121609

    Published calendar feeds can fail; hybrid sent-mail copies fixed

    Security vulnerabilities are addressed, and a hybrid shared-mailbox message-copy problem is fixed. Published calendar subscriptions can still return HTTP 500; a workaround is available.

    Build 15.2.1748.51
    Security 9 CVEs
    Known issues 1 open
    Replaced by KB5129956 →
  • Exchange Server · CU14
    Exchange Server 2019 CU14 Exchange Server 2019 CU14 ESU only Security update
    KB5121610

    Exchange security flaws addressed; hybrid mailbox wrappers fixed

    Security flaws are addressed, and a hybrid shared-mailbox message issue is fixed under specific mailbox and permission settings. Published calendar subscriptions stop refreshing and return HTTP 500 errors.

    Build 15.2.1544.46
    Security 9 CVEs
    Known issues 1 open
    Replaced by KB5129957 →
  • Exchange Server · CU23
    Exchange Server 2016 CU23 Exchange Server 2016 CU23 ESU only Security update
    KB5121611

    Eight security flaws addressed; published calendar feeds can fail

    Addresses eight Important vulnerabilities and fixes wrapper messages appearing in shared mailboxes in hybrid deployments. Published calendar subscriptions can still return HTTP 500.

    Build 15.1.2507.73
    Security 8 CVEs
    Known issues 1 open
    Replaced by KB5129958 →
  • SQL Server · CU8 + GDR
    SQL Server 2025 CU8 + GDR SQL Server 2025 CU8 + GDR Security update
    KB5122769

    Four critical remote-code flaws fixed; MSDASQL queries may fail

    Fixes 56 vulnerabilities, including four critical SQL Server remote-code execution flaws. Linked-server queries using MSDASQL with a provider string can fail, and queries during database recovery can trigger an access violation.

    Build 17.0.4085.5
    Security 56 CVEs 4 critical
    Known issues 2 open
    Replaced by KB5126967 →
  • SQL Server · GDR
    SQL Server 2025 GDR SQL Server 2025 GDR Security update
    KB5122770

    Critical database flaws addressed; linked-server queries may fail

    Addresses 56 SQL Server vulnerabilities, including four critical remote-code-execution flaws. Linked server queries using MSDASQL and a provider string can fail with error 7416.

    Build 17.0.1135.8
    Security 56 CVEs 4 critical
    Known issues 1 open
    Replaced by KB5128492 →
  • SQL Server · CU26 + GDR
    SQL Server 2022 CU26 + GDR SQL Server 2022 CU26 + GDR Security update
    KB5122768

    Remote-code flaws patched; two issues remain open

    The update fixes 52 vulnerabilities, including four critical remote-code-execution flaws. KB5126934 supersedes it, so use the newer update rather than installing this package.

    Build 16.0.4275.2
    Security 52 CVEs 4 critical
    Known issues 2 open
    Replaced by KB5126934 →
  • SQL Server · GDR
    SQL Server 2022 GDR SQL Server 2022 GDR Security update
    KB5122771

    Four critical database code-execution flaws patched

    Fixes 52 vulnerabilities, including four critical remote code execution flaws. Some linked server queries using MSDASQL can still fail with error 7416.

    Build 16.0.1200.5
    Security 52 CVEs 4 critical
    Known issues 1 open
    Replaced by KB5128493 →