---
id: "CVE-2021-27059"
kind: "vulnerability"
aliases: ["CVE-2021-27059"]
title: "Microsoft Office: Microsoft Office Remote Code Execution Vulnerability"
severity: "high"
cvss: 8.5
epss: 0.06076
exploited: true
status: "open"
category: "other"
products: [{"name": "Microsoft Office", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "microsoft-office", "other", "windows"]
not_affected_if: ["unpatched-builds-only"]
published_at: "2021-03-11T16:15:17+00:00"
first_seen_at: "2026-10-23T19:11:53+00:00"
updated_at: "2026-10-23T21:57:34+00:00"
sources: [{"source": "kev", "url": "https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-27059", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2021-27059", "first_seen_at": "2026-10-23T19:13:43+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-27059", "first_seen_at": "2026-10-23T21:57:34+00:00"}]
---

# Microsoft Office: Microsoft Office Remote Code Execution Vulnerability

Microsoft Office contains an unspecified flaw that allows remote code execution. CISA lists it in the Known Exploited Vulnerabilities catalog, so attackers are using it in real attacks.

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

## Affected

- vendor:Microsoft Office affected ? fixed ?

## How to check

Check each Office install's version and patch level against Microsoft's security update guide for CVE-2021-27059. unknown for the exact affected build list.

## Fix

Apply the Microsoft Office security updates per vendor instructions, as CISA requires. unknown for the specific patched build numbers.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-27059
- 2026-10-23T19:13:43+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2021-27059
- 2026-10-23T21:57:34+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-27059

## From the sources

Microsoft Office contains an unspecified vulnerability that allows for remote 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_