CVE-2024-21413
Published 2024-02-13 · Updated 2026-08-10 · Source secure@microsoft.com
Summary
CVE-2024-21413 is a critical-severity (CVSS 9.8) vulnerability in Microsoft Office Outlook. CISA added it to the Known Exploited Vulnerabilities catalog on February 6, 2025, which means exploitation in the wild has been confirmed; US federal agencies had to remediate it by February 27, 2025. CISA does not currently list it as used in ransomware campaigns. Microsoft has 390 vulnerabilities in the KEV catalog, 117 of them linked to ransomware.
All 390 known-exploited Microsoft vulnerabilities →Description
Microsoft Outlook Remote Code Execution Vulnerability
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CISA Known-Exploited Vulnerability
Product: Microsoft — Office Outlook
Name: Microsoft Outlook Improper Input Validation Vulnerability
Date added: 2025-02-06 · Due: 2025-02-27
Required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
References
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21413
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21413
- https://research.checkpoint.com/2024/the-risks-of-the-monikerlink-bug-in-microsoft-outlook-and-the-big-picture/
- https://www.vicarius.io/vsociety/posts/cve-2024-21413-critical-monikerlink-vulnerability-affecting-microsoft-outlook-detection-script
- https://www.vicarius.io/vsociety/posts/cve-2024-21413-critical-monikerlink-vulnerability-affecting-microsoft-outlook-mitigation-script
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-21413