---
id: CVE-2026-81390
title: >-
  Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker
  to disclose information locally.
summary: >-
  Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker
  to disclose information locally.
severity: medium
cvss: 5.5
cvssVector: 'CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N'
cwe:
  - CWE-125
vendor: microsoft
product: 365_apps
affected:
  - 365_apps
  - excel = 2016
  - microsoft_365
  - office_2016
  - office_2019
  - office_2021
  - office_2024
  - office_online_server < 16.0.10417.20207
patched:
  - office_online_server 16.0.10417.20207
published: '2026-09-08'
updated: '2026-09-17'
sourceUpdated: '2026-09-17T20:18:38.307'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-81390'
references:
  - url: 'https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-81390'
    label: secure@microsoft.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: partial
  timestamp: '2026-09-08T18:55:36.130511Z'
epss: 0.00541
epssPercentile: 0.43026
ingestedAt: '2026-09-08T19:08:49.631Z'
---

## Overview

Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information locally.

## Affected

- `365_apps`
- `excel = 2016`
- `microsoft_365`
- `office_2016`
- `office_2019`
- `office_2021`
- `office_2024`
- `office_online_server < 16.0.10417.20207`

## Remediation

Upgrade past the affected range:

- `office_online_server 16.0.10417.20207`