What’s Vulnerable › Vulnerabilities

CVE-2021-27053: Microsoft Excel Remote Code Execution Vulnerability

• Severity: medium (CVSS 6.8 v2.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-03-11 · updated 2026-08-19

Description

Microsoft Excel Remote Code Execution Vulnerability

Affected products

• Microsoft 365 Apps: all versions
• Microsoft Excel 2013 Service Pack 1: 2010-sp2, 2013-sp1, 2016
• Microsoft Office: 2019
• Microsoft Office Online Server: all versions
• Microsoft Office Web Apps: 2013-sp1
• Microsoft 365 Apps: from 16.0.1 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Excel 2013 Service Pack 1: from 13.0.0.0 before 14.0.7266.5000 — fixed in 14.0.7266.5000
• Microsoft Excel 2016: from 16.0.0.0 before 16.0.5134.1000 — fixed in 16.0.5134.1000
• Microsoft Office Web Apps Server 2013 Service Pack 1: from 15.0.1 before 15.0.5327.1000 — fixed in 15.0.5327.1000
• Microsoft Office: from 19.0.0 before https://aka.ms/OfficeSecurityReleases — fixed in https://aka.ms/OfficeSecurityReleases
• Microsoft Office Online Server: from 16.0.1 before 16.0.10372.20000 — fixed in 16.0.10372.20000

How to fix

Upgrade to a fixed version: Microsoft 365 Apps https://aka.ms/OfficeSecurityReleases; Microsoft Excel 2013 Service Pack 1 14.0.7266.5000; Microsoft Excel 2016 16.0.5134.1000; Microsoft Office Web Apps Server 2013 Service Pack 1 15.0.5327.1000; Microsoft Office https://aka.ms/OfficeSecurityReleases; Microsoft Office Online Server 16.0.10372.20000. Check the vendor advisory for mitigations.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-27053
• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-27053
• https://www.zerodayinitiative.com/advisories/ZDI-21-332/

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