IRONSMITHINTEL
HIGHCVSS7.5
|
Actively Exploited
|CISA KEV|CVE-2024-38112|Auth: none — unauthenticated|Reboot: required|Manual only

KB5040426: Windows Server Security Update (July 2024)

Microsoft Windows MSHTML Platform contains a spoofing vulnerability that has a high impact to confidentiality, integrity, and availability.

Published Jul 9, 2024 · Updated May 16, 2026
Why patchRisk explained in plain English
Worst-case scenarioIf unpatched

A remote attacker, without authentication, can achieve full data confidentiality loss, arbitrary modification of data, complete denial of service or system unavailability. Federal agencies are required to remediate by 2024-07-30 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Software Vulnerability (CWE-451) (CWE-451) vulnerability in Microsoft Windows. Exploitation requires remote network access, higher attack complexity, no authentication required, and user interaction required.

📧

Phishing link

→

🖼

Malicious file

🔓

Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

●Windows Administrators
●Systems Engineers
●IT Security
●Running windows 10 1507: v < 10.0.10240.20710; windows 10 1607: v < 10.0.14393.7159; windows 10 1809: v < 10.0.17763.6054; windows 10 21h2: v < 10.0.19044.4651; windows 10 22h2: v < 10.0.19045.4651; windows 11 21h2: v < 10.0.22000.3079; windows 11 22h2: v < 10.0.22621.3880; windows 11 23h2: v < 10.0.22631.3880; windows server 2008: -; windows server 2012: r2; windows server 2016: v < 10.0.14393.7159; windows server 2019: v < 10.0.17763.6054; windows server 2022: v < 10.0.20348.2582; windows server 2022 23h2: v < 10.0.25398.1009
Fixed inKB5040426, KB5040427, KB5040430, KB5040431, KB5040434, KB5040437, KB5040438, KB5040442, KB5040448, KB5040456, KB5040490, KB5040499 (applies to 31 product versions) — build 1.001, 10.0.10240.20710+
Real-world incidentsWhat we've seen

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2024-07-09 based on evidence of active exploitation in the wild. Federal agencies required to remediate by 2024-07-30.

How to patch

Manual download

For air-gapped servers or out-of-band deployment. Microsoft Update Catalog returns every OS-version variant of this update.

↗ Microsoft Update CatalogKB5040426

Manual remediation steps

Apply the Microsoft Security Update

Microsoft has released an official security update that fixes this vulnerability.

Required KB Updates

    1
    KB5040426 — https://support.microsoft.com/help/5040426
    1
    KB5040427 — https://support.microsoft.com/help/5040427
    1
    KB5040430 — https://support.microsoft.com/help/5040430
    1
    KB5040431 — https://support.microsoft.com/help/5040431
    1
    KB5040434 — https://support.microsoft.com/help/5040434
    1
    KB5040437 — https://support.microsoft.com/help/5040437
    1
    KB5040438 — https://support.microsoft.com/help/5040438
    1
    KB5040442 — https://support.microsoft.com/help/5040442
    1
    KB5040448 — https://support.microsoft.com/help/5040448
    1
    KB5040456 — https://support.microsoft.com/help/5040456
    1
    KB5040490 — https://support.microsoft.com/help/5040490
    1
    KB5040499 — https://support.microsoft.com/help/5040499

Supersedes: KB5034120, KB5039211, KB5039212, KB5039213, KB5039214, KB5039217, KB5039225, KB5039227, KB5039236, KB5039245, KB5039294

Affected Products

    1
    Windows 10 Version 1607 for 32-bit Systems
    1
    Windows 10 Version 1607 for x64-based Systems
    1
    Windows 10 Version 1809 for 32-bit Systems
    1
    Windows 10 Version 1809 for x64-based Systems
    1
    Windows 10 Version 21H2 for 32-bit Systems
    1
    Windows 10 Version 21H2 for ARM64-based Systems
    1
    Windows 10 Version 21H2 for x64-based Systems
    1
    Windows 10 Version 22H2 for 32-bit Systems
    1
    Windows 10 Version 22H2 for ARM64-based Systems
    1
    Windows 10 Version 22H2 for x64-based Systems
    1
    Windows 10 for 32-bit Systems
    1
    Windows 10 for x64-based Systems
    1
    Windows 11 Version 22H2 for ARM64-based Systems
    1
    Windows 11 Version 22H2 for x64-based Systems
    1
    Windows 11 Version 23H2 for ARM64-based Systems
    1
    Windows 11 Version 23H2 for x64-based Systems
    1
    Windows 11 version 21H2 for ARM64-based Systems
    1
    Windows 11 version 21H2 for x64-based Systems
    1
    Windows Server 2008 for 32-bit Systems Service Pack 2
    1
    Windows Server 2008 for 32-bit Systems Service Pack 2 (Server Core installation)
    1
    (…11 more product versions)

Fixed Build Numbers

    1
    1.001
    1
    10.0.10240.20710
    1
    10.0.14393.7159
    1
    10.0.17763.6054
    1
    10.0.19044.4651
    1
    10.0.19045.4651
    1
    10.0.20348.2582
    1
    10.0.22000.3079
    1
    10.0.22621.3880
    1
    10.0.22631.3880
    1
    (…3 more builds)

Installation Methods

Windows Update (recommended)

1
Settings → Windows Update → Check for updates
2
The security update is offered if your system is in scope
3
Restart when prompted — a reboot IS required to complete the install

Microsoft Update Catalog (manual download)

1
Open https://catalog.update.microsoft.com
2
Search for KB5040426
3
Download the package matching your OS architecture and Windows build
4
Run the .msu installer with administrator privileges
5
Restart when prompted

WSUS / SCCM / Intune

Approve KB5040426 for the affected products in your update management console.

Microsoft Download Center Links

    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5040426
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5040427
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5040430
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5040431
    1
    https://catalog.update.microsoft.com/v7/site/Search.aspx?q=KB5040434
    1
    (…7 more)

Verification

Confirm the update is installed:

Get-HotFix | Where-Object { $_.HotFixID -in @('KB5040426','KB5040427','KB5040430','KB5040431','KB5040434','KB5040437','KB5040438','KB5040442','KB5040448','KB5040456','KB5040490','KB5040499') }

References

    1
    Microsoft Security Response Center: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-38112
    1
    KB article: https://support.microsoft.com/help/5040426
    1
    KB article: https://support.microsoft.com/help/5040427
    1
    KB article: https://support.microsoft.com/help/5040430
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2024-38112
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-38112

Discovery Credit

Haifei Li with Check Point Research

PowerShell automationComing soon

No tested PowerShell script for this entry yet. We’re prioritising automation based on user demand.

References

↗ CVE-2024-38112↗ MSRC Advisory↗ NVD↗ KBKB5040426