CVE-2026-118714: Microsoft Excel heap-based buffer overflow in spreadsheet parsing

CVE-2026-118714 · Severity: high · CVSS 8.8 · Published 2026-11-10

Microsoft Excel, a widely used spreadsheet application, contains a heap-based buffer overflow vulnerability in its parsing logic. An attacker could exploit this flaw by sending a specially crafted spreadsheet file over a network to execute arbitrary code on the victim's machine. Successful exploitation could lead to complete system compromise, data theft, or deployment of malware.

Technologies: Microsoft Excel. Vendors: Microsoft.

Quick answers

Is CVE-2026-118714 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-118714 being exploited in the wild.
How severe is CVE-2026-118714?
High severity, with a CVSS score of 8.8, published 10 November 2026.
Which products and versions are affected?
Microsoft Excel.
Is there a fix for CVE-2026-118714?
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-2026-118714 attacked?
It is attacked over the network, in a software library.
Am I affected by CVE-2026-118714?
Check whether you run Microsoft 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 exists in Microsoft Excel's spreadsheet file parsing code. The vulnerability is triggered when processing malformed spreadsheet files and allows network-based code execution without requiring user authentication or special privileges. An attacker can craft a malicious Excel file that, when opened or processed by a vulnerable version, overwrites heap memory and achieves arbitrary code execution.

Affected products

  • Microsoft Excel

References

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