CVE-2026-124170: Microsoft Office Excel heap-based buffer overflow

CVE-2026-124170 · Severity: high · CVSS 7.5 · Published 2026-11-10

Microsoft Office Excel, a spreadsheet application used across organizations for data analysis and reporting, contains a heap-based buffer overflow vulnerability that could allow an attacker to execute arbitrary code remotely. An attacker can exploit this flaw over the network by sending a specially crafted Excel file, potentially leading to unauthorized access, data theft, or system compromise.

Technologies: Microsoft Office Excel. Vendors: Microsoft.

Quick answers

Is CVE-2026-124170 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-124170 being exploited in the wild.
How severe is CVE-2026-124170?
High severity, with a CVSS score of 7.5, published 10 November 2026.
Which products and versions are affected?
Microsoft Office Excel.
Is there a fix for CVE-2026-124170?
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-2026-124170 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-124170?
Check whether you run Microsoft Office Excel. 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 in Microsoft Office Excel allows remote code execution when processing malformed spreadsheet files. The vulnerability requires network access and can be triggered by opening a specially crafted Excel document; no authentication or user interaction beyond opening the file is required. An attacker gains arbitrary code execution in the context of the application.

Affected products

  • Microsoft Office Excel

Timeline

  • 2026-11-10: disclosed

References

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