# CVE-2024-21413: Microsoft Outlook Improper Input Validation Vulnerability

Source: https://junglewise.ai/threats/cve-2024-21413-microsoft-outlook-improper-input-validation-vulnerability  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-02-06. Updated: 2026-05-09  
License: CC BY 4.0 with a link back

CVE-2024-21413 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2025-02-06

Microsoft Outlook contains an improper input validation vulnerability, known as 'MonikerLink', that allows for remote code execution. An attacker can bypass Office Protected View to open malicious files in editing mode, potentially leading to full system compromise without user interaction.

Technologies: [Microsoft Office Outlook](https://junglewise.ai/threats/technologies/office-outlook), [Microsoft Outlook](https://junglewise.ai/threats/technologies/outlook). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2024-21413 exploited in the wild?** Yes. CVE-2024-21413 is known to be exploited in the wild, first recorded on 6 February 2025. Treat it as urgent.

**How severe is CVE-2024-21413?** Critical severity, with a CVSS score of 9.8, published 6 February 2025.

**Which products and versions are affected?** Microsoft 365 Apps for Enterprise; Microsoft Office Long Term Servicing Channel 2021; Microsoft Office 2019; Microsoft Office 2016.

**Is there a fix for CVE-2024-21413?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2024-21413 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2024-21413?** Check whether you run Microsoft Office Outlook or Microsoft Outlook. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Microsoft 365 Apps for Enterprise
- Microsoft Office Long Term Servicing Channel 2021
- Microsoft Office 2019
- Microsoft Office 2016

## Timeline

- 2024-11-21: disclosed: Initial disclosure and technical description by Check Point Research.
- 2025-02-06: kev added: Added to CISA's Known Exploited Vulnerabilities (KEV) Catalog.
- 2025-02-27: other: CISA due date for federal agencies to apply mitigations.

## Related threats

- [Microsoft Office Outlook path traversal in pathname handling](https://junglewise.ai/threats/cve-2026-124228-improper-limitation-of-a-pathname-to-a-restricted-directory-path)
- [Microsoft Office Outlook use of uninitialized resource code execution](https://junglewise.ai/threats/cve-2026-124227-use-of-uninitialized-resource-in-microsoft-office-outlook-allows)
- [Microsoft Office Outlook user warning spoofing vulnerability](https://junglewise.ai/threats/cve-2026-124194-microsoft-office-outlook-missing-user-interaction-for)
- [Microsoft Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123384-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an)
- [Microsoft Office Outlook heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-123383-heap-based-buffer-overflow-in-microsoft-office-outlook-allows-an)