CVE-2026-123375: Microsoft Office Outlook stack-based buffer overflow

CVE-2026-123375 · Severity: high · CVSS 8.8 · Published 2026-11-10

Microsoft Office Outlook, widely used for email and calendar management in enterprises, contains a stack-based buffer overflow vulnerability that allows an attacker to execute arbitrary code on affected systems over the network without requiring user authentication. An attacker could exploit this to gain complete control of a user's computer, access sensitive emails and business data, or use the system as a foothold for further network attacks.

Technologies: Microsoft Office Outlook. Vendors: Microsoft.

Quick answers

Is CVE-2026-123375 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-123375 being exploited in the wild.
How severe is CVE-2026-123375?
High severity, with a CVSS score of 8.8, published 10 November 2026.
Which products and versions are affected?
Microsoft Office Outlook.
Is there a fix for CVE-2026-123375?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-123375 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-123375?
Check whether you run Microsoft Office Outlook. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

A stack-based buffer overflow in Microsoft Office Outlook can be triggered remotely by an attacker without authentication, enabling arbitrary code execution with the privileges of the user running Outlook. The vulnerability exists in the mail client's processing of network-received data. A fix is available from Microsoft.

Affected products

  • Microsoft Office Outlook

Timeline

  • 2026-11-10: disclosed

References

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