CVE-2021-43905Network attack vector

Remote code execution after user interaction

Published Dec 15, 2021 · Updated May 28, 2026

Remote code execution in Microsoft Office app before 18.2110.13110.0 allows remote attackers to execute code after user interaction. Microsoft has not published the affected component or the operation performed on untrusted input. Exploitation requires the victim to interact with attacker-controlled content, and successful exploitation runs code in the app's security context.

CVSS severity9.6
Critical
EPSS probability2.82%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Microsoft Office app before 18.2110.13110.0 allows remote attackers to execute code after user interaction. Microsoft has not published the affected component or the operation performed on untrusted input. Exploitation requires the victim to interact with attacker-controlled content, and successful exploitation runs code in the app's security context.

The record

CVE
CVE-2021-43905
Published
Dec 15, 2021
Updated
May 28, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Dec 15, 2021CVE publishedPublication date reported by the CVE source.
  2. May 28, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

6.8NIST NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
9.6Microsoft CorporationCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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