CVE-2026-78519: Microsoft Office Outlook Remote Code Execution Vulnerability

Published Sep 8, 2026
·
Updated

Microsoft Office Outlook Remote Code Execution Vulnerability

Other sources

Use of uninitialized resource in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.

Microsoft

Affected Software

11 affected componentsFixes available
Microsoft Microsoft Office Outlook
Microsoft Office LTSC 2024 for 32-bit editions<16.0.17932.20960
16.0.17932.20960
Microsoft Office LTSC 2021 for 32-bit editions<16.0.14334.20896
16.0.14334.20896
Microsoft Office 2019 for 64-bit editions<16.0.10417.20204
16.0.10417.20204
Microsoft 365 Apps for Enterprise<16.0.20326.20136
16.0.20326.20136
Microsoft Outlook 2016<16.0.5569.1000
16.0.5569.1000
Microsoft Office LTSC 2024 for 64-bit editions<16.0.17932.20960
16.0.17932.20960
Microsoft Outlook 2016<16.0.5569.1000
16.0.5569.1000
Microsoft Office LTSC 2021 for 64-bit editions<16.0.14334.20896
16.0.14334.20896
Microsoft 365 Apps for Enterprise<16.0.20326.20136
16.0.20326.20136
Microsoft Office 2019 for 32-bit editions<16.0.10417.20204
16.0.10417.20204

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 16.0.17932.20960
  2. Upgrade

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

    Fixed in 16.0.14334.20896
  3. Upgrade

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

    Fixed in 16.0.20326.20136
  4. Upgrade

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

    Fixed in 16.0.5569.1000Patch KB5002919
  5. Upgrade

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

    Fixed in 16.0.10417.20204

Event History

Sep 8, 2026
CVE Published
via Microsoft·02:00 PM
Data Sourced
via Microsoft·02:00 PM
DescriptionSeverityWeaknessAffected Software
Updated
via Microsoft·02:00 PM
Affected Software
Updated
via Microsoft·02:00 PM
DescriptionSeverity
CVE Published
via MITRE·05:18 PM
Data Sourced
via MITRE·05:18 PM
DescriptionSeverity
Data Sourced
via NVD·06:20 PM
DescriptionSeverityWeakness

Frequently Asked Questions

1

Does exploitation require an authenticated account or a user action?

No privileges are required by the attacker, but user interaction is required. The vulnerability is remotely exploitable over a network with low attack complexity.

2

What is the potential impact if exploitation succeeds?

Successful exploitation can allow code execution and has high potential impact on confidentiality, integrity, and availability.

3

Which Outlook and Office product families are listed as affected?

The affected software list includes Microsoft 365 Apps for Enterprise, Outlook 2016, Microsoft Office Outlook, Office 2019 for 64-bit editions, and Office LTSC 2021 and 2024 for both 32-bit and 64-bit editions.

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