CVE-2021-22681: Rockwell Automation Logix Designer authentication bypass in Logix Controllers

CVE-2021-22681 · Severity: critical · CVSS 9.8 · Exploited in the wild · Published 2026-03-05

Multiple Rockwell Automation industrial controllers and design software products contain a critical security flaw that allows unauthorized users to bypass authentication. These systems are used to control and monitor industrial processes in manufacturing and infrastructure. If exploited, an attacker could gain full control over the industrial hardware, potentially leading to operational disruption, physical damage, or safety risks.

Technologies: Apple Multiple Products, Rockwell Automation Studio 5000 Logix Designer. Vendors: Apple, Rockwell Automation.

Quick answers

Is CVE-2021-22681 exploited in the wild?
Yes. CVE-2021-22681 is known to be exploited in the wild, first recorded on 5 March 2026. Treat it as urgent.
How severe is CVE-2021-22681?
Critical severity, with a CVSS score of 9.8, published 5 March 2026.
Which products and versions are affected?
Rockwell Automation RSLogix 5000 16 through 20; Rockwell Automation Studio 5000 Logix Designer 21 and later.
Is there a fix for CVE-2021-22681?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2021-22681 attacked?
It is attacked over the network, in an operating system.
Am I affected by CVE-2021-22681?
Check whether you run Apple Multiple Products, Rockwell Automation CompactLogix, Rockwell Automation ControlLogix or one of the others listed at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability (CWE-522) exists because Rockwell Automation Studio 5000 Logix Designer and RSLogix 5000 use a static or insufficiently protected key to verify communications with Logix controllers. An unauthenticated attacker with network access to the controller can discover this key and use it to bypass the verification mechanism. This allows the attacker to authenticate with the controller as if they were using authorized design software. Successful exploitation grants the attacker the ability to modify controller configurations or logic. This vulnerability has been observed being exploited in the wild.

Affected products

  • Rockwell Automation Studio 5000 Logix Designer 21 and later
  • Rockwell Automation RSLogix 5000 16 through 20
  • Rockwell Automation CompactLogix (1768, 1769, 5370, 5380, 5480)
  • Rockwell Automation ControlLogix (5550, 5560, 5570, 5580)
  • Rockwell Automation GuardLogix (5570, 5580)
  • Rockwell Automation DriveLogix (5560, 5730, 1794-L34)
  • Rockwell Automation SoftLogix 5800

Timeline

  • 2021-02-25: advisory: Initial ICSA-21-056-03 advisory published
  • 2026-03-05: kev added: Added to CISA Known Exploited Vulnerabilities catalog

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