What’s Vulnerable › Vulnerabilities

CVE-2021-31176: Microsoft Office Remote Code Execution Vulnerability

• Severity: medium (CVSS 6.8 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 3.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-05-11 · updated 2026-06-17
• Weakness: CWE-416

Description

Microsoft Office Remote Code Execution Vulnerability

Affected products

• Microsoft 365 Apps: all versions
• Microsoft Office: 2013-sp1, 2016, 2019
• Microsoft Office Online Server: all versions
• Microsoft Office Web Apps Server: 2013-sp1
• Microsoft 365 Apps: from 16.0.1 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Office 2013 Service Pack 1: from 15.0.0 before 15.0.5345.1002 — fixed in 15.0.5345.1002
• Microsoft Office: from 19.0.0 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases; Microsoft Office 2013 Service Pack 1 15.0.5345.1002; Microsoft Office https://aka.ms/OfficeSecurityReleases. Check the vendor advisory for mitigations.

References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31176
• https://www.zerodayinitiative.com/advisories/ZDI-21-575/
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-31176
• https://www.zerodayinitiative.com/advisories/ZDI-21-575/

Get alerted when CVE-2021-31176 or the next vulnerability affects your stack