CVE-2026-20953: Microsoft Office Remote Code Execution Vulnerability

Published Jan 13, 2026
·
Updated

Microsoft Office Remote Code Execution Vulnerability

Other sources

Use after free in Microsoft Office allows an unauthorized attacker to execute code locally.

Microsoft

Affected Software

24 affected componentsFixes available
Microsoft 365 Apps
Microsoft 365 Apps
Microsoft Office=2016
Microsoft Office=2016
Microsoft Office=2019
Microsoft Office=2019
Microsoft Office Long Term Servicing Channel=2021
Microsoft Office Long Term Servicing Channel=2021
Microsoft Office Long Term Servicing Channel Macos=2021
Microsoft Office Long Term Servicing Channel=2024
Microsoft Office Long Term Servicing Channel=2024
Microsoft Office Long Term Servicing Channel Macos=2024
Microsoft Office LTSC 2024 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2016<16.0.5535.1000
16.0.5535.1000
Microsoft Office LTSC for Mac 2024<16.105.26011018
16.105.26011018
Microsoft Office 2016<16.0.5535.1000
16.0.5535.1000
Microsoft Office LTSC 2021 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC for Mac 2021<16.105.26011018
16.105.26011018
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2024 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office LTSC 2021 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2019 for 32-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft Office 2019 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in https://aka.ms/OfficeSecurityReleases
  2. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 16.0.5535.1000Patch KB5002826
  3. Upgrade

    Upgrade to a fixed release to a version that resolves this vulnerability.

    Fixed in 16.105.26011018

Event History

Jan 13, 2026
CVE Published
via Microsoft·04:00 PM
Data Sourced
via Microsoft·04:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·04:00 PM
Affected Software
Updated
via Microsoft·04:00 PM
Description
CVE Published
via MITRE·05:56 PM
Data Sourced
via MITRE·05:56 PM
DescriptionSeverity
Data Sourced
via NVD·06:16 PM
DescriptionSeverityWeaknessAffected Software
Jan 14, 2026
News Published
via The Register·12:36 AM
News Published
via The Register·12:39 AM

Frequently Asked Questions

1

What is the severity of CVE-2026-20953?

CVE-2026-20953 is classified as a critical vulnerability due to its potential to allow remote code execution.

2

How do I fix CVE-2026-20953?

To remediate CVE-2026-20953, apply the latest security updates provided by Microsoft for affected versions of Office.

3

What types of Microsoft Office products are affected by CVE-2026-20953?

CVE-2026-20953 affects multiple versions of Microsoft Office, including Office 2016, Office 2019, Office LTSC 2021, and Office LTSC 2024.

4

Can CVE-2026-20953 be exploited without user interaction?

Yes, CVE-2026-20953 can be exploited through malicious documents that cause the affected Office software to execute harmful code.

5

What does 'use after free' mean in the context of CVE-2026-20953?

'Use after free' in CVE-2026-20953 refers to a programming flaw where the software continues to use a memory resource after it has been freed, potentially leading to code execution vulnerabilities.

Contact

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