Summary
Impact: Remote Code Execution. Microsoft rating: Important. Not known to be exploited — Exploitation Less Likely. Customer action: Required.
Details
According to the CVSS metric, user interaction is required (UI:R). What interaction would the user have to do?
An attacker must send a user a malicious Office file and convince them to open it.
According to the CVSS metric, the attack complexity is high (AC:H). What does that mean for this vulnerability?
Successful exploitation depends on specific memory conditions in the affected application that the attacker cannot fully control. These conditions can make exploitation unreliable.
Is the Preview Pane an attack vector for this vulnerability?
No, the Preview Pane is not 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 7.5
Microsoft Office Outlook Remote Code Execution Vulnerability
Use of uninitialized resource 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-2026-124227 Microsoft Office Outlook Remote Code Execution Vulnerability - HTML
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-124227
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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