---
id: "CVE-2026-118707"
page: "https://infrastack.ai/live/CVE-2026-118707"
kind: "vulnerability"
aliases: ["CVE-2026-118707"]
title: "Microsoft Excel: heap overflow lets a remote attacker run code"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "Office LTSC 2024", "fixed": ["16.0.17932.21140"], "affected": ">= 16.0.0, < 16.0.17932.21140", "ecosystem": "vendor"}, {"name": "Office LTSC 2021", "fixed": ["16.0.14334.21048"], "affected": ">= 16.0.1, < 16.0.14334.21048", "ecosystem": "vendor"}, {"name": "Office for Mac", "fixed": ["16.115.26110837"], "affected": "< 16.115.26110837", "ecosystem": "vendor"}, {"name": "Microsoft 365 Apps for Enterprise", "fixed": ["Current Channel 2610 build 20527.20196"], "affected": ">= 16.0.1, < November 10 2026 build per channel", "ecosystem": "vendor"}]
ecosystems: []
tags: ["excel", "macos", "microsoft-office", "other", "user-interaction", "windows"]
not_affected_if: []
published_at: "2026-11-10T19:19:45+00:00"
first_seen_at: "2026-11-10T19:24:52+00:00"
updated_at: "2026-11-10T23:09:31+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118707", "first_seen_at": "2026-11-10T19:24:52+00:00"}, {"source": "analyst", "url": "https://nvd.nist.gov/vuln/detail/cve-2026-118707", "first_seen_at": "2026-11-10T23:09:31+00:00", "cites": ["https://nvd.nist.gov/vuln/detail/cve-2026-118707", "https://learn.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates"]}]
exploit_sources: []
---

# Microsoft Excel: heap overflow lets a remote attacker run code

Link for people: https://infrastack.ai/live/CVE-2026-118707 (this .md is for agents)

A heap-based buffer overflow in Microsoft Office Excel lets an unauthorized attacker run code over a network. The sources give no further detail on how the file or request is delivered.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- vendor:Office LTSC 2024 affected >= 16.0.0, < 16.0.17932.21140 fixed 16.0.17932.21140
- vendor:Office LTSC 2021 affected >= 16.0.1, < 16.0.14334.21048 fixed 16.0.14334.21048
- vendor:Office for Mac affected < 16.115.26110837 fixed 16.115.26110837
- vendor:Microsoft 365 Apps for Enterprise affected >= 16.0.1, < November 10 2026 build per channel fixed Current Channel 2610 build 20527.20196

## How to check

In Excel open File > Account > About Excel and compare the build with the fixed builds: LTSC 2024 < 16.0.17932.21140, LTSC 2021 < 16.0.14334.21048, Mac < 16.115.26110837, Microsoft 365 Apps < the November 10 2026 build for your channel (https://aka.ms/OfficeSecurityReleases). Also check Office 2019/2021/2024 retail installs, which the CNA list may include.

## Fix

Update Office to the November 10, 2026 security release: Microsoft 365 Apps per https://aka.ms/OfficeSecurityReleases (Current Channel 2610 build 20527.20196); Office LTSC 2024 16.0.17932.21140 or later; Office LTSC 2021 16.0.14334.21048 or later; Office for Mac 16.115.26110837 or later.

## Timeline

- 2026-11-10T19:24:52+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118707
- 2026-11-10T23:09:31+00:00 analyst https://nvd.nist.gov/vuln/detail/cve-2026-118707 — MSRC page is JS-only, not read. Product/fixed builds from Microsoft's CNA record (via NVD mirror); Nov 10 2026 Office release notes on Learn list the builds. CVSS vector UI:R: needs a user to open a crafted file. Not exploited per sources. Nothing marked verified (MSRC entry not read).

## Documents

- [advisory] NVD CVE-2026-118707 (CNA data from Microsoft) https://nvd.nist.gov/vuln/detail/cve-2026-118707
- [fix] Microsoft Office security updates release notes (Nov 10, 2026) https://learn.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates

## From the sources

Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.

---

_Free to read, with fair use of about 60 pages a minute. For higher limits or API access: sales@infrastack.ai_