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CVE-2026-78519

Microsoft Outlook vulnerability

8.8 HIGHEPSS 0.82%
  1. Published8 Sept 2026

Description

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

CVSS 3.1 breakdown

Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionRequired
ScopeUnchanged
ConfidentialityHigh
IntegrityHigh
AvailabilityHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Affected products

Microsoft 365 Appsall versions
Microsoft Office 2019all versions
Microsoft Office 2021all versions
Microsoft Office 2024all versions
Microsoft Outlook2016

Remediation

No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.

References

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Frequently asked

Is CVE-2026-78519 being actively exploited?

CVE-2026-78519 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.82%.

How severe is CVE-2026-78519?

CVE-2026-78519 has a CVSS 3.1 base score of 8.8, rated high. EPSS estimates a 0.82% probability of exploitation.

Which products are affected by CVE-2026-78519?

Affected products include Microsoft 365 Apps, Microsoft Office 2019, Microsoft Office 2021, Microsoft Office 2024, Microsoft Outlook.

How do I fix CVE-2026-78519?

Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.

How Secuno handles this

Secuno correlates vulnerabilities like CVE-2026-78519 against the real software inventory on every managed device, as each hourly inventory arrives. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.

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Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.