CVE-2026-77898: Microsoft Office Remote Code Execution Vulnerability

Published Sep 8, 2026
·
Updated

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

Other sources

Microsoft Office Remote Code Execution Vulnerability

Microsoft

Affected Software

11 affected componentsFixes available
Microsoft Office LTSC for Mac 2024
Microsoft Office 365 for Mac
Microsoft 365 Apps for Enterprise<16.0.20326.20138
16.0.20326.20138
Microsoft Office LTSC 2024 for 64-bit editions<16.0.17932.20976
16.0.17932.20976
Microsoft Office 2019 for 32-bit editions<16.0.10417.20207
16.0.10417.20207
Microsoft Office LTSC for Mac 2021
Microsoft Office 2019 for 64-bit editions<16.0.10417.20207
16.0.10417.20207
Microsoft Office LTSC 2021 for 64-bit editions<16.0.14334.20906
16.0.14334.20906
Microsoft Office LTSC 2021 for 32-bit editions<16.0.14334.20906
16.0.14334.20906
Microsoft 365 Apps for Enterprise<16.0.20326.20138
16.0.20326.20138
Microsoft Office LTSC 2024 for 32-bit editions<16.0.17932.20976
16.0.17932.20976

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 16.0.20326.20138
  2. Upgrade

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

    Fixed in 16.0.17932.20976
  3. Upgrade

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

    Fixed in 16.0.10417.20207
  4. Upgrade

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

    Fixed in 16.0.14334.20906

Event History

Sep 8, 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·05:13 PM
Data Sourced
via MITRE·05:13 PM
DescriptionSeverity
Data Sourced
via NVD·06:20 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

Does exploitation require prior authentication or user interaction?

No privileges are required, but user interaction is required. The attack vector is network-based.

2

How difficult is exploitation expected to be?

The vulnerability is rated as requiring high attack complexity, despite being network-reachable and requiring no privileges.

3

Which Office product editions are identified as affected?

The listed products are Microsoft 365 Apps for Enterprise; Microsoft Office 365 for Mac; Office LTSC for Mac 2021 and 2024; Office LTSC 2021 and 2024 for 64-bit editions; and Office 2019 for 32-bit and 64-bit editions.

Contact

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