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Vulnerabilities

Vulnerability · CVE-2024-21413

Microsoft Outlook Improper Input Validation Vulnerability

Published Feb 13, 2024 · catalog updated Aug 10, 2026 · Microsoft Office Outlook

Patch now

CVE-2024-21413 is in the CISA known-exploited catalog, due Feb 27, 2025. Confirm Microsoft Office Outlook against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Gaps on this record

  • No version range is stored. A customer cannot check an installed version against this record.
Severity
Critical9.8
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
94.66%
Remediation
Remediation guidance
Affected products
cpe microsoft/365 apps · cpe microsoft/office 2016 · cpe microsoft/office 2019 · cpe microsoft/office long term servicing channel · vendor Microsoft Office Outlook

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. Initial-access exploit intelligence.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe microsoft/365 appsversion unspecified
  • cpe microsoft/office 2016version unspecified
  • cpe microsoft/office 2019version unspecified
  • cpe microsoft/office long term servicing channel2021
  • vendor Microsoft Office Outlookversion unspecified

How to fix CVE-2024-21413

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2024-21413 is in the CISA known-exploited catalog, due Feb 27, 2025. Confirm Microsoft Office Outlook against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with microsoft/office long term servicing channel 2021. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

What should an analyst verify?

CWE-20: Improper Input Validation. EPSS 94.66%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Feb 13, 2024 · Catalog

    Detected

    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.

  2. Feb 6, 2025 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

  3. Feb 27, 2025 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

  4. Aug 10, 2026 · Catalog

    Updated

    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.

Sources

  • CERT-FRGovernment advisoryCVE-2024-21413

    \[Mise à jour du 15 mars 2024\] Ajout de précision concernant les défi-réponses NTLM \[Mise à jour du 22 février 2024\] Ajout de recommandations et de précisions sur le fonctionnement de la vulnérabilité. La vulnérabilité CVE-2024-21413 permet à un attaquant de contourner les mes

    cert.ssi.gouv.fr
  • CISA KEVConfirmed exploitationCVE-2024-21413

    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.

    cisa.gov
  • CVE.orgVulnerability recordCVE-2024-21413

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2024-21413

    30-day exploitation probability 94.7%

    first.org
  • NIST NVDVulnerability recordCVE-2024-21413

    Microsoft Outlook Remote Code Execution Vulnerability

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2024-21413

    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.

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.