---
id: "CVE-2026-21514"
kind: "vulnerability"
aliases: ["CVE-2026-21514"]
title: "Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to\u2026"
severity: "high"
cvss: 7.8
epss: null
exploited: true
status: "open"
category: "other"
products: [{"name": "Microsoft Office", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft 365 apps", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "microsoft office long term servicing channel", "fixed": [], "affected": "= 2021", "ecosystem": "vendor"}, {"name": "microsoft office long term servicing channel", "fixed": [], "affected": "= 2024", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "microsoft-office", "microsoft-word", "other", "windows"]
not_affected_if: ["unknown"]
published_at: "2026-02-10T00:00:00+00:00"
first_seen_at: "2026-10-23T19:11:51+00:00"
updated_at: "2026-10-23T23:44:51+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-21514", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-21514", "first_seen_at": "2026-10-23T23:44:51+00:00"}]
---

# Reliance on untrusted inputs in a security decision in Microsoft Office Word allows an unauthorized attacker to…

Microsoft Office Word has a flaw where it relies on untrusted input when making a security decision. An authorized local user can use it to elevate their privileges, and CISA reports it is being exploited in the wild.

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

## Affected

- vendor:Microsoft Office affected ? fixed ?
- vendor:microsoft 365 apps affected ? fixed ?
- vendor:microsoft office long term servicing channel affected = 2021 fixed ?
- vendor:microsoft office long term servicing channel affected = 2024 fixed ?

## How to check

Check the installed Microsoft Office Word build against Microsoft's security update guide for CVE-2026-21514; the sources do not give the affected build numbers.

## Fix

Apply the Microsoft security update for CVE-2026-21514 per vendor instructions; if no mitigation is available, discontinue use of the product as CISA directs (sources do not name the patched version).

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2026-21514
- 2026-10-23T23:44:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-21514

## From the sources

Microsoft Office Word contains a reliance on untrusted inputs in a security decision vulnerability that could allow an authorized attacker to elevate privileges locally.

CISA required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_