---
id: "CVE-2021-22681"
kind: "vulnerability"
aliases: ["CVE-2021-22681"]
title: "Rockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSLogix 5000 Versions 16 through 20 use a\u2026"
severity: "critical"
cvss: 9.8
epss: null
exploited: true
status: "open"
category: "infrastructure"
products: [{"name": "Rockwell Multiple Products", "fixed": [], "affected": "", "ecosystem": "vendor"}, {"name": "rockwellautomation factorytalk services platform", "fixed": [], "affected": ">= 2.10", "ecosystem": "vendor"}, {"name": "rockwellautomation rslogix 5000", "fixed": [], "affected": ">= 16, <= 20", "ecosystem": "vendor"}, {"name": "rockwellautomation studio 5000 logix designer", "fixed": [], "affected": ">= 21.0", "ecosystem": "vendor"}]
ecosystems: ["vendor"]
tags: ["exploited", "industrial-control", "infrastructure", "logix-controllers", "rockwell", "studio-5000"]
not_affected_if: ["isolated-network", "no-logix-controllers"]
published_at: "2021-03-03T18:15:14+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-2021-22681", "first_seen_at": "2026-10-23T19:11:51+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2021-22681", "first_seen_at": "2026-10-23T23:44:51+00:00"}]
---

# Rockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSLogix 5000 Versions 16 through 20 use a…

Rockwell Studio 5000 Logix Designer may let an attacker discover a key used to verify that Logix controllers talk only to Rockwell design software. With that key, an unauthorized application can connect to Logix controllers.

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

## Affected

- vendor:Rockwell Multiple Products affected ? fixed ?
- vendor:rockwellautomation factorytalk services platform affected >= 2.10 fixed ?
- vendor:rockwellautomation rslogix 5000 affected >= 16, <= 20 fixed ?
- vendor:rockwellautomation studio 5000 logix designer affected >= 21.0 fixed ?

## Fix

Apply mitigations per the vendor instructions referenced by CISA, or discontinue use of the affected product if mitigations are unavailable.

## Timeline

- 2026-10-23T19:11:51+00:00 kev https://www.cisa.gov/known-exploited-vulnerabilities-catalog?search_api_fulltext=CVE-2021-22681
- 2026-10-23T23:44:51+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2021-22681

## From the sources

Rockwell Automation Studio 5000 Logix Designer Versions 21 and later, and RSLogix 5000 Versions 16 through 20 use a key to verify Logix controllers are communicating with Rockwell Automation CompactLogix 1768, 1769, 5370, 5380, 5480: ControlLogix 5550, 5560, 5570, 5580; DriveLogix 5560, 5730, 1794-L34; Compact GuardLogix 5370, 5380; GuardLogix 5570, 5580; SoftLogix 5800. Rockwell Automation Studio 5000 Logix Designer Versions 21 and later and RSLogix 5000: Versions 16 through 20 are vulnerable because an unauthenticated attacker could bypass this verification mechanism and authenticate with Rockwell Automation CompactLogix 1768, 1769, 5370, 5380, 5480: ControlLogix 5550, 5560, 5570, 5580; DriveLogix 5560, 5730, 1794-L34; Compact GuardLogix 5370, 5380; GuardLogix 5570, 5580; SoftLogix 5800.

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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_