CVE-2026-65661: Microsoft Office Remote Code Execution Vulnerability

Published Aug 11, 2026
·
Updated

Heap-based buffer overflow in Microsoft Office allows an unauthorized attacker to execute code locally.

Other sources

Microsoft Office Remote Code Execution Vulnerability

Microsoft

Affected Software

10 affected componentsFixes available
Microsoft Office 2019 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 Office 2016<16.0.5565.1001, <16.0.5565.1000
16.0.5565.100116.0.5565.1000
Microsoft Office 2016<16.0.5565.1001, <16.0.5565.1000
16.0.5565.100116.0.5565.1000
Microsoft Office LTSC 2021 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 LTSC 2024 for 64-bit editions<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
Microsoft 365 Apps for Enterprise<https://aka.ms/OfficeSecurityReleases
https://aka.ms/OfficeSecurityReleases
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

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 16.0.5565.1001Fixed in 16.0.5565.1000Patch KB5002900

Event History

Aug 11, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeakness
Data Sourced
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
Description
CVE Published
via MITRE·05:04 PM
Data Sourced
via MITRE·05:04 PM
DescriptionSeverity
Data Sourced
via NVD·05:18 PM
DescriptionSeverityWeakness
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Frequently Asked Questions

1

What is the severity of CVE-2026-65661?

CVE-2026-65661 has a high severity rating of 7.8.

2

What is CVE-2026-65661?

CVE-2026-65661 is a heap-based buffer overflow vulnerability in Microsoft Office that allows unauthorized remote code execution.

3

Which Microsoft Office versions are affected by CVE-2026-65661?

CVE-2026-65661 affects Microsoft Office 2016, Microsoft 365 Apps for Enterprise, Microsoft Office 2019, and Microsoft Office LTSC versions.

4

How do I fix CVE-2026-65661?

To fix CVE-2026-65661, install the latest security updates provided by Microsoft for the affected Office versions.

5

What are the potential impacts of CVE-2026-65661?

The potential impacts of CVE-2026-65661 include unauthorized code execution, which could lead to data loss or system compromise.

Contact

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