---
id: "CVE-2020-17144"
kind: "vulnerability"
aliases: ["CVE-2020-17144"]
title: "Microsoft Exchange Server: Microsoft Exchange Server Remote Code Execution Vulnerability"
severity: "high"
cvss: 8.8
epss: 0.36514
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Microsoft Exchange Server", "fixed": [], "affected": "", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exchange-server", "exploited", "infrastructure", "self-hosted", "windows"]
not_affected_if: ["exchange-online", "patched-server"]
published_at: "2020-12-10T00:15:16+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-2020-17144", "first_seen_at": "2026-10-23T19:11:53+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2020-17144", "first_seen_at": "2026-10-23T19:13:44+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2020-17144", "first_seen_at": "2026-10-23T21:57:35+00:00"}]
---

# Microsoft Exchange Server: Microsoft Exchange Server Remote Code Execution Vulnerability

Microsoft Exchange Server does not properly validate cmdlet arguments, letting an attacker run code remotely on the server. CISA lists it as actively exploited in the wild.

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

## Affected

- vendor:Microsoft Exchange Server affected ? fixed ?

## Fix

Apply the Microsoft updates for Exchange Server per vendor instructions, as CISA requires; the specific patched build numbers are not in the sources.

## Timeline

- 2026-10-23T19:11:53+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2020-17144
- 2026-10-23T19:13:44+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2020-17144
- 2026-10-23T21:57:35+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2020-17144

## From the sources

Microsoft Exchange Server improperly validates cmdlet arguments which allow an attacker to perform remote code execution.

CISA required action: Apply updates per vendor instructions.

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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_