CVE-2024-21378: Microsoft 365 apps code injection vulnerability

Microsoft · 365 Apps

Microsoft Outlook Remote Code Execution Vulnerability

8.8 CVSS 3.1 High EPSS 11% · top 4.2% CWE-94 · Code injection

8.8CVSS 3.1 base score

11%EPSS exploitation probability, 30 days

NoNot in CISA KEV

4Affected product versions listed by NVD

2References

10 Aug 2026Last modified by NVD

Description

Microsoft Outlook Remote Code Execution Vulnerability

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected products

4 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

365 Apps Microsoft

Office Microsoft

Office Long Term Servicing Channel Microsoft

Outlook Microsoft

References

Link	Tags
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21378	PatchVendor Advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21378	PatchVendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2024-21378), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.