CVE-2022-26901Known exploitation

Remote code execution via XLS use-after-free

Published Apr 15, 2022 · Updated Jan 2, 2025

Remote code execution in Microsoft Excel 2013, 2016, Office 2016, Office 2019 for Mac, LTSC 2021, Office Online Server, Office Web Apps Server 2013, and Microsoft 365 Apps allows attackers to execute code via a malicious XLS file. The XLS parser fails to validate an object exists before operating on it, causing a use-after-free condition that runs code in the current process. Exploitation requires a user to open the crafted file or visit a malicious page; successful exploitation can compromise confidentiality, integrity, and availability.

CVSS severity7.8
High
EPSS probability2.53%
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 Excel 2013, 2016, Office 2016, Office 2019 for Mac, LTSC 2021, Office Online Server, Office Web Apps Server 2013, and Microsoft 365 Apps allows attackers to execute code via a malicious XLS file. The XLS parser fails to validate an object exists before operating on it, causing a use-after-free condition that runs code in the current process. Exploitation requires a user to open the crafted file or visit a malicious page; successful exploitation can compromise confidentiality, integrity, and availability.

The record

CVE
CVE-2022-26901
Published
Apr 15, 2022
Updated
Jan 2, 2025
Vendor
Microsoft
Product
Microsoft Office 2016
Classifications
T1203
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 15, 2022CVE publishedPublication date reported by the CVE source.
  2. Jan 2, 2025Record 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 <16.0.5305.1000

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

Microsoft · Microsoft Office 2016version=16.0.0 <16.0.5305.1000
Microsoft · Microsoft Excel 2016version=16.0.0.0 <16.0.5305.1000
Microsoft · Microsoft Office LTSC for Mac 2021version=16.0.1 <16.60.22041000
Microsoft · Microsoft Office 2013version=15.0.0 <15.0.5441.1000
Microsoft · Microsoft Excel 2013version=15.0.0.0 <15.0.5441.1000
Microsoft · Microsoft Office 2019 for Macversion=16.0.0 <16.60.22041000
Microsoft · Microsoft Office LTSC 2021version=16.0.1 <https://aka.ms/OfficeSecurityReleases
Microsoft · Microsoft Office Online Serverversion=16.0.1 <16.0.10385.20001
Microsoft · Microsoft Office Web Apps Server 2013version=15.0.1 <15.0.5441.1000
Microsoft · Microsoft 365 Apps for enterpriseversion=16.0.1 <https://aka.ms/OfficeSecurityReleases

Published CVSS scores

6.8NVDAV:N/AC:M/Au:N/C:P/I:P/A:P
7.8MicrosoftCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesunauthenticated
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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