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CriticalCVE-2026-78519active

Microsoft Office Outlook Remote Code Execution Vulnerability

Published September 8, 2026Updated September 8, 2026

Source data

Overview

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

Impact & technical details

Remote Code Execution

How could an attacker exploit the vulnerability? In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted email to the victim. Exploitation of the vulnerability might involve either a victim opening a specially crafted email with an affected version of Microsoft Outlook software, or a victim's Outlook application displaying a preview of a specially crafted email . This could result in the attacker executing remote code on the victim's machine.

Is the Preview Pane an attack vector for this vulnerability? Yes, the Preview Pane is an attack vector.

CVSS base score
8.8 / 10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C

Highest base score supplied by MSRC for this record; the vector belongs to that score. Ratings can vary by product. Microsoft Important is displayed as High; Moderate is displayed as Medium.

Affected products

  • Microsoft 365 Apps for Enterprise for 32-bit Systems
  • Microsoft 365 Apps for Enterprise for 64-bit Systems
  • Microsoft Office 2019 for 32-bit editions
  • Microsoft Office 2019 for 64-bit editions
  • Microsoft Office LTSC 2021 for 32-bit editions
  • Microsoft Office LTSC 2021 for 64-bit editions
  • Microsoft Office LTSC 2024 for 32-bit editions
  • Microsoft Office LTSC 2024 for 64-bit editions
Show all 10 affected products
  • Microsoft Outlook 2016 (32-bit edition)
  • Microsoft Outlook 2016 (64-bit edition)

Source guidance

Remediation

  • Release Notes

At least one Microsoft vendor-fix reference is available. Check each affected product for its applicable update, prerequisites, and supported version.

GTP recommendation · Rule-based guidance

Recommended next step

Review affected systems and prioritize deployment of the vendor security update.

Authoritative sources & updates

Findings and update information come from the linked publishers. GTP compiles the public record and provides the recommendation above. CVSS ratings shown here come from Microsoft. NVD references provide additional public context.

Managed by GTP?

Griffin Technology Partners managed customers may receive additional environment-specific security guidance and remediation assistance through their managed services relationship.

Security bulletins are provided for informational purposes and compiled from authoritative public sources. Vulnerability applicability varies by environment. Validate affected products, configuration, compatibility requirements, and vendor guidance before making production changes.