CVE-2021-40485

Code execution via undisclosed spreadsheet-processing flaw

Published Oct 13, 2021 · Updated Feb 28, 2025

Code injection in affected Microsoft Excel products allows local users to execute code after a user opens a crafted spreadsheet. Microsoft has not published the affected parser, file record, or unsafe operation responsible for processing the crafted input. Exploitation requires user interaction and runs code in the user's security context, permitting confidentiality, integrity, and availability compromise.

CVSS severity7.8
High
EPSS probability2.68%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Code injection in affected Microsoft Excel products allows local users to execute code after a user opens a crafted spreadsheet. Microsoft has not published the affected parser, file record, or unsafe operation responsible for processing the crafted input. Exploitation requires user interaction and runs code in the user's security context, permitting confidentiality, integrity, and availability compromise.

The record

CVE
CVE-2021-40485
Published
Oct 13, 2021
Updated
Feb 28, 2025
Vendor
Microsoft
Product
Microsoft Office 2019
Classifications
CWE-94, T1204.002
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 13, 2021CVE publishedPublication date reported by the CVE source.
  2. Feb 28, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=19.0.0 <https://aka.ms/OfficeSecurityReleases

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Office 2019version=19.0.0 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Excel 2016version=16.0.0.0 <16.0.5227.1000
Microsoft · Microsoft Office LTSC for Mac 2021version=16.0.1 <16.54.21101001
Microsoft · Microsoft SharePoint Enterprise Server 2013version=15.0.0 <15.0.5389.1000
Microsoft · Microsoft Excel 2013version=15.0.0.0 <15.0.5389.1000
Microsoft · Microsoft Office 2019 for Macversion=16.0.0 <16.54.21101001
Microsoft · Microsoft Office LTSC 2021version=16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Office Online Serverversion=16.0.1 <16.0.10379.20000
Microsoft · Microsoft 365 Apps for enterpriseversion=16.0.1 <https://aka.ms/OfficeSecurityReleases

Published CVSS scores

7.8Microsoft CorporationCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
6.8NISTAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8NISTCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-94Improper Control of Generation of Code ('Code Injection')
T1204.002Malicious File

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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