CVE-2021-38655
mediumpriority · track · 29EPSS 0.064 · 94 %ileEURUUSEPSS · scored 2026-10-27
Microsoft Excel Remote Code Execution Vulnerability
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedMicrosoft 365 Apps for Enterprise for 32-bit Systemsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft 365 Apps for Enterprise for 64-bit Systemsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Excel 2013 RT Service Pack 1msrc_csaf
5381.1000:Security Update:https://support.microsoft.com/kb/5002014
https://support.microsoft.com/kb/5002014 - FixedMicrosoft Excel 2013 Service Pack 1 (32-bit editions)msrc_csaf
5381.1000:Security Update:https://support.microsoft.com/kb/5002014
https://support.microsoft.com/kb/5002014 - FixedMicrosoft Excel 2013 Service Pack 1 (64-bit editions)msrc_csaf
5381.1000:Security Update:https://support.microsoft.com/kb/5002014
https://support.microsoft.com/kb/5002014 - FixedMicrosoft Excel 2016 (32-bit edition)msrc_csaf
5215.1000:Security Update:https://support.microsoft.com/kb/5002003
https://support.microsoft.com/kb/5002003 - FixedMicrosoft Excel 2016 (64-bit edition)msrc_csaf
5215.1000:Security Update:https://support.microsoft.com/kb/5002003
https://support.microsoft.com/kb/5002003 - FixedMicrosoft Office 2019 for 32-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office 2019 for 64-bit editionsmsrc_csaf
https://aka.ms/OfficeSecurityReleases:Security Update:https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates - FixedMicrosoft Office 2019 for Macmsrc_csaf
16.53.21091200:Security Update:https://go.microsoft.com/fwlink/p/?linkid=831049
https://go.microsoft.com/fwlink/p/?linkid=831049 - FixedMicrosoft Office Online Servermsrc_csaf
10378.20000:Security Update:https://support.microsoft.com/kb/5001999
https://support.microsoft.com/kb/5001999 - FixedMicrosoft Office Web Apps Server 2013 Service Pack 1msrc_csaf
5381.1000:Security Update:https://support.microsoft.com/kb/5002009
https://support.microsoft.com/kb/5002009
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.8–8.8
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (44)
Products and version ranges known to be affected.
- Microsoft Microsoft 365 Apps for Enterprise16.0.1 → https://aka.ms/OfficeSecurityReleasesenisa_euvdEU
- Microsoft 365 Apps for Enterprise for 32-bit Systems< https://aka.ms/OfficeSecurityReleasesmsrc_csafUS
- Microsoft 365 Apps for Enterprise for 64-bit Systems< https://aka.ms/OfficeSecurityReleasesmsrc_csafUS
advisories (1)
Vendor and ecosystem advisories describing this.
- msrc_CVE-2021-38655Microsoft Excel Remote Code Execution Vulnerability2021-09-14csaf · msrc_csafUS
To determine the support lifecycle for your software, see the Microsoft Support Lifecycle: https://support.microsoft.com/lifecycle
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (10)
External citations — patches, advisories, analysis.
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-38655cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2021-38655cnnvd
- https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-38655cnnvd
- https://vigilance.fr/vulnerability/Microsoft-365-Apps-vulnerabilities-of-September-2021-36409cnnvd
- https://www.cybersecurity-help.cz/vdb/SB2021091443cnnvd
- https://www.zerodayinitiative.com/advisories/ZDI-21-1080/cnnvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-38655enisa_euvd
- https://msrc.microsoft.com/update-guide/vulnerability/CVE-2021-38655nvd
Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.
Free scan