What’s Vulnerable › Vulnerabilities

CVE-2021-31949: Microsoft Outlook Remote Code Execution Vulnerability

• Severity: medium (CVSS 6.8 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 2.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-06-08 · updated 2026-06-17
• Weakness: CWE-94

Description

Microsoft Outlook Remote Code Execution Vulnerability

Affected products

• Microsoft 365 Apps: all versions
• Microsoft Office: 2019
• Microsoft Outlook: 2013-sp1, 2016
• Microsoft 365 Apps: from 16.0.1 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Outlook 2013 Service Pack 1: from 15.0.0.0 before 15.0.5475.1000 — fixed in 15.0.5475.1000
• Microsoft Office: from 19.0.0 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Outlook 2016 for Mac: from 16.0.0.0 before 16.0.5356.1000. — fixed in 16.0.5356.1000.

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases; Microsoft Outlook 2013 Service Pack 1 15.0.5475.1000; Microsoft Office https://aka.ms/OfficeSecurityReleases; Microsoft Outlook 2016 for Mac 16.0.5356.1000.. Check the vendor advisory for mitigations.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31949
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31949

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