CVE-2026-118730: Microsoft Office Excel use-after-free code execution

CVE-2026-118730 · Severity: high · CVSS 8.8 · Published 2026-11-10

Microsoft Office Excel, a widely-used spreadsheet application, contains a use-after-free vulnerability that allows an attacker to execute arbitrary code on a user's computer when a maliciously crafted Excel file is opened. This could enable an attacker to gain full control of the affected system, steal sensitive data, or install ransomware.

Technologies: Microsoft Office Excel. Vendors: Microsoft.

Quick answers

Is CVE-2026-118730 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-118730 being exploited in the wild.
How severe is CVE-2026-118730?
High severity, with a CVSS score of 8.8, published 10 November 2026.
Which products and versions are affected?
Microsoft Office Excel.
Is there a fix for CVE-2026-118730?
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-2026-118730 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-118730?
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 use-after-free vulnerability exists in Excel's memory handling, allowing remote code execution via a crafted file. The attacker can trigger the vulnerability by sending a malicious Excel document to a user, who must open it for exploitation; the vulnerability is reached during file parsing. Successful exploitation grants code execution in the context of the user running Excel.

Affected products

  • Microsoft Office Excel

Timeline

  • 2026-11-10: disclosed

References

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