# CVE-2026-105718: Microsoft Office Excel out-of-bounds read in parsing

Source: https://junglewise.ai/threats/cve-2026-105718-out-of-bounds-read-in-microsoft-office-excel-allows-an  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-13. Updated: 2026-10-16  
License: CC BY 4.0 with a link back

CVE-2026-105718 · Severity: high · CVSS 8.8 · Published 2026-10-13

Microsoft Office Excel contains a vulnerability that allows an attacker to execute code on a user's computer over a network by sending a specially crafted Excel file. This could lead to unauthorized access to sensitive financial data, formulas, or personal information stored in spreadsheets, or allow the attacker to install malware on the system.

Technologies: [Microsoft 365 Apps](https://junglewise.ai/threats/technologies/365-apps), [Microsoft 365](https://junglewise.ai/threats/technologies/microsoft-365), [Microsoft Office 2021](https://junglewise.ai/threats/technologies/office-2021), [Microsoft Office 2024](https://junglewise.ai/threats/technologies/office-2024), [Microsoft Office Excel](https://junglewise.ai/threats/technologies/office-excel), [Microsoft Office Online Server](https://junglewise.ai/threats/technologies/office-online-server). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2026-105718 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-105718 being exploited in the wild.

**How severe is CVE-2026-105718?** High severity, with a CVSS score of 8.8, published 13 October 2026.

**Which products and versions are affected?** Microsoft Office Excel.

**Is there a fix for CVE-2026-105718?** 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-2026-105718 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-105718?** Check whether you run Microsoft 365 Apps, Microsoft 365, Microsoft Office 2021 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 vulnerability in Excel's file parsing logic allows remote code execution when a specially crafted Office document is opened. The vulnerability requires user interaction (opening a malicious file), but no authentication is needed. An attacker can achieve arbitrary code execution on the victim's machine in the context of the user running Excel.

## Affected products

- Microsoft Office Excel

## Timeline

- 2026-10-13: disclosed

## References

- [https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-105718](https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-105718)

## Related threats

- [Microsoft Office Excel unsafe deserialization in file parsing](https://junglewise.ai/threats/cve-2026-124229-deserialization-of-untrusted-data-in-microsoft-office-excel)
- [Microsoft Office Excel use-after-free remote code execution](https://junglewise.ai/threats/cve-2026-124187-use-after-free-in-microsoft-office-excel-allows-an-unauthorized)
- [Microsoft Office Excel buffer over-read information disclosure](https://junglewise.ai/threats/cve-2026-124183-buffer-over-read-in-microsoft-office-excel-allows-an)
- [Microsoft Office Excel out-of-bounds read information disclosure](https://junglewise.ai/threats/cve-2026-124179-out-of-bounds-read-in-microsoft-office-excel-allows-an)
- [Microsoft Office Excel out-of-bounds read](https://junglewise.ai/threats/cve-2026-124178-out-of-bounds-read-in-microsoft-office-excel-allows-an)