---
id: "CVE-2026-118293"
page: "https://infrastack.ai/live/CVE-2026-118293"
kind: "vulnerability"
aliases: ["CVE-2026-118293"]
title: "Microsoft Excel: out-of-bounds read lets an attacker run code when a user opens a crafted file"
severity: "high"
cvss: 8.8
epss: null
exploited: false
status: "open"
category: "other"
products: [{"name": "Microsoft Office LTSC 2021", "fixed": ["16.0.14334.21048"], "affected": "16.0.1 to < 16.0.14334.21048", "ecosystem": "vendor"}, {"name": "Microsoft Office LTSC 2024", "fixed": ["16.0.17932.21140"], "affected": "16.0.0 to < 16.0.17932.21140", "ecosystem": "vendor"}, {"name": "Microsoft Office for Mac (365, LTSC 2021, LTSC 2024)", "fixed": ["16.115.26110837"], "affected": "< 16.115.26110837", "ecosystem": "vendor"}, {"name": "Microsoft 365 Apps for Enterprise", "fixed": ["2610 build 20527.20196"], "affected": "builds before the Nov 10, 2026 release (Current Channel 2610 build 20527.20196)", "ecosystem": "vendor"}, {"name": "Office Online Server", "fixed": ["16.0.10417.20236"], "affected": "< 16.0.10417.20236", "ecosystem": "vendor"}]
ecosystems: []
tags: ["excel", "file-open", "macos", "microsoft-office", "office-ltsc", "other", "windows"]
not_affected_if: ["patched-nov-2026-build"]
published_at: "2026-11-10T19:19:42+00:00"
first_seen_at: "2026-11-10T19:24:51+00:00"
updated_at: "2026-11-10T23:14:00+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-118293", "first_seen_at": "2026-11-10T19:24:51+00:00"}, {"source": "analyst", "url": "https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118293", "first_seen_at": "2026-11-10T23:14:00+00:00", "cites": ["https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118293", "https://learn.microsoft.com/en-us/OfficeUpdates/microsoft365-apps-security-updates"]}]
exploit_sources: []
---

# Microsoft Excel: out-of-bounds read lets an attacker run code when a user opens a crafted file

Link for people: https://infrastack.ai/live/CVE-2026-118293 (this .md is for agents)

Out-of-bounds read (CWE-125, with integer underflow CWE-191) in Microsoft Office Excel lets an unauthorized attacker execute code. Microsoft rates it CVSS 8.8 and the vector requires user interaction (opening a crafted file). Microsoft lists no known exploitation. Fixed in the November 10, 2026 Office updates.

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

## Affected

- vendor:Microsoft Office LTSC 2021 affected 16.0.1 to < 16.0.14334.21048 fixed 16.0.14334.21048
- vendor:Microsoft Office LTSC 2024 affected 16.0.0 to < 16.0.17932.21140 fixed 16.0.17932.21140
- vendor:Microsoft Office for Mac (365, LTSC 2021, LTSC 2024) affected < 16.115.26110837 fixed 16.115.26110837
- vendor:Microsoft 365 Apps for Enterprise affected builds before the Nov 10, 2026 release (Current Channel 2610 build 20527.20196) fixed 2610 build 20527.20196
- vendor:Office Online Server affected < 16.0.10417.20236 fixed 16.0.10417.20236

## How to check

In any Office app: File > Account > About (Windows) or About Excel (Mac) and compare the build with the fixed one. Fixed builds: Microsoft 365 Apps/Office 2021/2024 Retail Current Channel 2610 build 20527.20196 (Monthly Enterprise 2610 20527.20194, 2609 20430.20264, 2608 20326.20320; Semi-Annual 2610 20527.20192, 2609 20430.20262, 2608 20326.20318); Office LTSC 2024 16.0.17932.21140; Office LTSC 2021 16.0.14334.21048; Office for Mac 16.115.26110837 (build 26110837). Office Online Server: per the CNA record, below 16.0.10417.20236.

## Fix

Update Office to the November 10, 2026 release (see how-to-check for builds per channel); Mac: 16.115 (Build 26110837) via Microsoft AutoUpdate.

## Timeline

- 2026-11-10T19:24:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-118293
- 2026-11-10T23:14:00+00:00 analyst https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118293 — Nov 2026 Patch Tuesday Excel RCE (CWE-125/191, CVSS 8.8, UI:R, E:U: no known exploitation). MSRC page is JS-only and unreadable; fixed builds taken from Microsoft Learn Office security release notes (Nov 10) and CNA record via OpenCVE. Product ranges not vendor-page verified except fix builds. No posts searched (fresh, no exploitation).

## Documents

- [advisory] MSRC: Microsoft Office Excel Remote Code Execution Vulnerability CVE-2026-118293 https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-118293
- [fix] Release notes for Microsoft Office security updates (Nov 10, 2026 lists CVE-2026-110053 under Word) https://learn.microsoft.com/en-us/OfficeUpdates/microsoft365-apps-security-updates

## From the sources

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to execute code over a network.

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