CVE-2026-109496: Microsoft Office Visio heap-based buffer overflow

CVE-2026-109496 · Severity: high · CVSS 8.8 · Published 2026-11-10

Microsoft Office Visio is a diagramming and visualization tool used by organizations for creating flowcharts, network diagrams, and business process models. A heap-based buffer overflow vulnerability in Visio allows an attacker to execute arbitrary code on a user's computer when the user opens a specially crafted file, potentially leading to full system compromise.

Technologies: Microsoft Office Visio. Vendors: Microsoft.

Quick answers

Is CVE-2026-109496 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-109496 being exploited in the wild.
How severe is CVE-2026-109496?
High severity, with a CVSS score of 8.8, published 10 November 2026.
Which products and versions are affected?
Microsoft Office Visio.
Is there a fix for CVE-2026-109496?
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-2026-109496 attacked?
It is attacked over the network.
Am I affected by CVE-2026-109496?
Check whether you run Microsoft Office Visio. 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 heap-based buffer overflow exists in Microsoft Office Visio's file parsing functionality that can be triggered when processing a malicious Visio file. The vulnerability requires user interaction to open the crafted file over a network but does not require authentication. Exploitation allows arbitrary code execution in the context of the user running Visio.

Affected products

  • Microsoft Office Visio

Timeline

  • 2026-11-10: disclosed

References

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