CVE-2026-102855: Microsoft Office Visio heap buffer overflow

CVE-2026-102855 · Severity: high · CVSS 8.8 · Published 2026-10-13

Microsoft Office Visio is a diagramming and visualization tool used for business process mapping and technical drawings. A heap buffer overflow vulnerability allows an attacker to execute arbitrary code on a user's computer by sending a specially crafted file over the network, potentially leading to data theft, malware installation, or system compromise.

Technologies: Microsoft 365 Apps, Microsoft Office 2021, Microsoft Office 2024, Microsoft Office Visio. Vendors: Microsoft.

Quick answers

Is CVE-2026-102855 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-102855 being exploited in the wild.
How severe is CVE-2026-102855?
High severity, with a CVSS score of 8.8, published 13 October 2026.
Which products and versions are affected?
Microsoft Office Visio.
Is there a fix for CVE-2026-102855?
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-2026-102855 attacked?
It is attacked over the network.
Am I affected by CVE-2026-102855?
Check whether you run Microsoft 365 Apps, Microsoft Office 2021, Microsoft Office 2024 or one of the others listed. 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 logic that can be triggered by a malicious document sent over the network. The vulnerability allows remote code execution without requiring user authentication, though the user must interact with the malicious file (open it). An attacker can leverage this to achieve code execution in the context of the user running Visio.

Affected products

  • Microsoft Office Visio

Timeline

  • 2026-10-13: disclosed

References

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