---
id: "CVE-2021-42292"
kind: "vulnerability"
aliases: ["CVE-2021-42292"]
title: "Microsoft Office: Microsoft Excel Security Feature Bypass"
severity: "high"
cvss: 7.8
epss: 0.43005
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Office", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["excel", "exploited", "infrastructure", "microsoft-office", "windows"]
not_affected_if: ["unknown"]
published_at: "2021-11-10T01:19:47+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:35+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-42292", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-42292", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-42292", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Microsoft Office: Microsoft Excel Security Feature Bypass

A security feature bypass in Microsoft Excel lets a local user get arbitrary code execution. The sources say it is actively exploited in the wild, with CISA listing it in KEV.

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

## Affected

- vendor:Microsoft Office affected ? fixed ?

## Fix

Apply Microsoft's updates for Office per vendor instructions, as CISA requires; the sources do not name the patched build.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-42292
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-42292
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-42292

## From the sources

A security feature bypass vulnerability in Microsoft Excel would allow a local user to perform arbitrary code execution.

CISA required action: Apply updates per vendor instructions.

---

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