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CVE-2024-21413

Microsoft Outlook Improper Input Validation

9.8 CRITICALActively exploited (CISA KEV)Public exploitEPSS 94.7%
  1. Published13 Feb 2024
  2. Added to CISA KEV6 Feb 2025
  3. Remediation due27 Feb 2025
Actively exploited (CISA KEV)

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.

Added to KEV: 6 Feb 2025Federal remediation due: 27 Feb 2025

Description

Microsoft Outlook Remote Code Execution Vulnerability

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

Microsoft 365 Appsall versions
Microsoft Office 2016all versions
Microsoft Office 2019all versions
Microsoft Office Long Term Servicing Channel2021

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2024-21413 being actively exploited?

Yes. CVE-2024-21413 is listed in the CISA Known Exploited Vulnerabilities (KEV) catalog, added 6 Feb 2025.

How severe is CVE-2024-21413?

CVE-2024-21413 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 94.7% probability of exploitation.

Which products are affected by CVE-2024-21413?

Affected products include Microsoft 365 Apps, Microsoft Office 2016, Microsoft Office 2019, Microsoft Office Long Term Servicing Channel.

How do I fix CVE-2024-21413?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2024-21413 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. Because it is on the CISA KEV list, Secuno flags any affected asset as top-priority automatically. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.