Summary
Impact: Remote Code Execution. Microsoft rating: Critical. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
How could an attacker exploit the vulnerability?
Exploitation of the vulnerability requires that a user open or preview a specially crafted email with an affected version of Microsoft Outlook software. This could result in the attacker executing remote code on the victim's machine. In an email attack scenario, an attacker could exploit the vulnerability by sending the specially crafted email to the user and convincing the user to read the message.
Is the Preview Pane an attack vector for this vulnerability?
Yes, the Preview Pane is an attack vector.
Security updates
16.0.14334.21048 — https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
https — https://learn.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates
Vulnerabilities 1
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High 8.8
Microsoft Office Outlook Remote Code Execution Vulnerability
Release of invalid pointer or reference in Microsoft Office Outlook allows an unauthorized attacker to execute code over a network.
Revision history
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#1
Information published.
References
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CVE-2026-111309 Microsoft Office Outlook Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-111309
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Microsoft Exploitability Index
https://www.microsoft.com/en-us/msrc/exploitability-index?rtc=1
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Microsoft Support Lifecycle
https://support.microsoft.com/lifecycle
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Common Vulnerability Scoring System
https://www.first.org/cvss