IRONSMITHINTEL
CRITICALCVSS9.8
|
Actively Exploited
|CISA KEV|CVE-2024-21413|Auth: none — unauthenticated|Reboot: required|Manual only

KB5002467: Windows Server Security Update (February 2024)

Microsoft Outlook contains an improper input validation vulnerability that allows for remote code execution. Successful exploitation of this vulnerability would allow an attacker to bypass the Office Protected View and open in editing mode rather than protected mode.

Published Feb 13, 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 2025-02-27 under CISA BOD 22-01.

How the attack worksNo clicks needed

This is a Improper Input Validation (CWE-20) vulnerability in Microsoft Office Outlook. Microsoft Outlook Remote Code Execution Vulnerability Exploitation requires remote network access, low attack complexity, no authentication required, and no user interaction required.

📧

Phishing link

→

🖼

Malicious file

🔓

Server compromised

Am I affected?Quick check

Probably yes if any of these apply:

●Exchange Administrators
●Messaging Team
●IT Security
●Running 365 apps: -; office 2016: -; office 2019: -; office long term servicing channel: 2021
Fixed inKB5002467, KB5002519, KB5002522, KB5002537 (applies to 8 product versions) — build 16.0.5435.1000, 16.0.5435.1001+
Real-world incidentsWhat we've seen

Active exploitation documented in the wild. Threat-research write-up: https://research.checkpoint.com/2024/the-risks-of-the-monikerlink-bug-in-microsoft-outlook-and-the-big-picture/

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 CatalogKB5002467

Manual remediation steps

Apply the Microsoft Security Update

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

Required KB Updates

    1
    KB5002467 — https://support.microsoft.com/help/5002467
    1
    KB5002519 — https://support.microsoft.com/help/5002519
    1
    KB5002522 — https://support.microsoft.com/help/5002522
    1
    KB5002537 — https://support.microsoft.com/help/5002537

Affected Products

    1
    Microsoft 365 Apps for Enterprise for 32-bit Systems
    1
    Microsoft 365 Apps for Enterprise for 64-bit Systems
    1
    Microsoft Office 2016 (32-bit edition)
    1
    Microsoft Office 2016 (64-bit edition)
    1
    Microsoft Office 2019 for 32-bit editions
    1
    Microsoft Office 2019 for 64-bit editions
    1
    Microsoft Office LTSC 2021 for 32-bit editions
    1
    Microsoft Office LTSC 2021 for 64-bit editions

Fixed Build Numbers

    1
    16.0.5435.1000
    1
    16.0.5435.1001
    1
    https://aka.ms/OfficeSecurityReleases

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 (may or may not be required for this update)

Microsoft Update Catalog (manual download)

1
Open https://catalog.update.microsoft.com
2
Search for KB5002467
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 KB5002467 for the affected products in your update management console.

Microsoft Download Center Links

    1
    https://www.microsoft.com/download/details.aspx?familyid=0019c7f4-e4f2-4741-8cfb-0fd2311b71f4
    1
    https://www.microsoft.com/download/details.aspx?familyid=0754e80a-a661-4e4c-b876-7288e83d0e26
    1
    https://www.microsoft.com/download/details.aspx?familyid=2b476112-870d-451c-a7d7-e513e72ec383
    1
    https://www.microsoft.com/download/details.aspx?familyid=3f798cca-1d11-494e-82a5-f8e8cbe4d716
    1
    https://www.microsoft.com/download/details.aspx?familyid=96a56f04-fed0-4743-b518-23b904e9368e
    1
    (…3 more)

Verification

Confirm the update is installed:

Get-HotFix | Where-Object { $_.HotFixID -in @('KB5002467','KB5002519','KB5002522','KB5002537') }

References

    1
    Microsoft Security Response Center: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21413
    1
    KB article: https://support.microsoft.com/help/5002467
    1
    KB article: https://support.microsoft.com/help/5002519
    1
    KB article: https://support.microsoft.com/help/5002522
    1
    NVD entry: https://nvd.nist.gov/vuln/detail/CVE-2024-21413
    1
    CISA KEV: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-21413

Discovery Credit

Haifei Li of Check Point Research (https://research.checkpoint.com/)

PowerShell automationComing soon

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

References

↗ CVE-2024-21413↗ MSRC Advisory↗ NVD↗ KBKB5002467