CVE-2026-88151: Microsoft Office Excel out-of-bounds read

CVE-2026-88151 · Severity: medium · CVSS 6.5 · Published 2026-10-13

Microsoft Office Excel contains an out-of-bounds read vulnerability that allows an attacker to disclose sensitive information over the network. An attacker can exploit this by crafting a malicious Excel file that, when opened, triggers the vulnerability and leaks data from the application's memory. This could result in exposure of confidential spreadsheet data or other sensitive information processed by Excel.

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

Quick answers

Is CVE-2026-88151 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-88151 being exploited in the wild.
How severe is CVE-2026-88151?
Medium severity, with a CVSS score of 6.5, published 13 October 2026.
Which products and versions are affected?
Microsoft Office Excel.
Is there a fix for CVE-2026-88151?
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-2026-88151 attacked?
It is attacked over the network, in a web application.
Am I affected by CVE-2026-88151?
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

An out-of-bounds read in Microsoft Office Excel allows information disclosure through network-based exploitation. The vulnerability does not require authentication or user interaction beyond opening a crafted malicious file. An attacker gains the ability to read and disclose information from memory regions accessed by the application.

Affected products

  • Microsoft Office Excel

Timeline

  • 2026-10-13: disclosed

References

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