CVE-2021-27059Known exploitationNetwork attack vector

Remote code execution via undisclosed processing flaw

Published Mar 11, 2021 · Updated Aug 19, 2026

Remote code execution in Microsoft Office 2010 SP2, 2013 SP1, and 2016 allows remote authenticated users to execute code. Microsoft has not published the affected component, crafted input, or incorrect operation that triggers execution. Exploitation requires high privileges and user interaction, and successful code runs with the affected user's rights.

CVSS severityUnavailable
Unscored
EPSS probability6.08%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Remote code execution in Microsoft Office 2010 SP2, 2013 SP1, and 2016 allows remote authenticated users to execute code. Microsoft has not published the affected component, crafted input, or incorrect operation that triggers execution. Exploitation requires high privileges and user interaction, and successful code runs with the affected user's rights.

The record

CVE
CVE-2021-27059
Published
Mar 11, 2021
Updated
Aug 19, 2026
Vendor
Microsoft
Product
Microsoft Office 2016
Classifications
T1203
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 11, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 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?

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

  1. Affected versionversion=16.0.0 <16.0.5134.1000

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Microsoft · Microsoft Office 2016version=16.0.0 <16.0.5134.1000
Microsoft · Microsoft Office 2013version=15.0.0 <publication
Microsoft · Microsoft Office 2010version=13.0.0.0 <14.0.7266.5000

Published CVSS scores

7.6MicrosoftCVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C

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
Privilegesauthenticated
Known exploitationReported
Public exploitUnconfirmed

Weakness, pattern, technique

T1203Exploitation for Client Execution

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.

Reported exploitation

Technologies

Your stack

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Your stack

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