# CVE-2021-22681: Rockwell Multiple Products Insufficient Protected Credentials

> An unauthenticated attacker can bypass verification mechanisms to authenticate with Rockwell Automation Logix controllers, potentially gaining unauthorized control.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Yes, since 5 Mar 2026 (CISA KEV)
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 3 Mar 2021
- **Updated:** 6 Mar 2026
- **Also known as:** GHSA-pvh9-p4pw-h78q

## What is CVE-2021-22681?

CVE-2021-22681 is a critical authentication bypass vulnerability in Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers, published on 3 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-522 (Insufficiently Protected Credentials)

## Which versions are affected by CVE-2021-22681?

It affects 3 products.


Products: Rockwellautomation Factorytalk Services Platform, Rockwellautomation Rslogix 5000, Rockwellautomation Studio 5000 Logix Designer.

## How do I fix CVE-2021-22681?

No fix has been published for CVE-2021-22681 yet. Limit exposure of the affected software until one is available. US federal agencies must fix it by 26 Mar 2026.

## Is CVE-2021-22681 being exploited?

Yes. Attackers have exploited CVE-2021-22681 in the wild since at least 5 Mar 2026.

Public exploit code:

- ▎ Open, runnable proof of concept + IEC 62443-4-2 (SL 2) mapping + a phased rollout for CVE-2021-22681 — the unpatchable Rockwell Logix hardcoded-key flaw behind the 2026 water-sector attacks. Reproduces the fix principle with open tooling; sized for small water utilities. (github_poc): https://github.com/pcrosby-1990/cip-security-poc

## Other vulnerabilities in Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers

- [CVE-2020-14516](https://insights.sbomify.com/CVE-2020-14516/): Weak cryptography in Rockwell Automation FactoryTalk Services Platform (critical 10.0)
- [CVE-2024-21917](https://insights.sbomify.com/CVE-2024-21917/): Rockwell Automation FactoryTalk® Service Platform Service Token Vulnerability (critical 9.8)
- [CVE-2020-6967](https://insights.sbomify.com/CVE-2020-6967/): Deserialization in Rockwell Automation All versions of FactoryTalk Diagnostics software, a subsystem of the FactoryTalk Services Platform (critical 9.8)
- [CVE-2024-21915](https://insights.sbomify.com/CVE-2024-21915/): Rockwell Automation FactoryTalk® Service Platform Elevated Privileges Vulnerability Through Web Service Functionality (critical 9.0)
- [CVE-2020-12033](https://insights.sbomify.com/CVE-2020-12033/): Missing authorization in Rockwell Automation FactoryTalk Services Platform (high 8.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2021-22681 and fix it if it is affected.

What it is: CVE-2021-22681 is a critical authentication bypass vulnerability in Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers, published on 3 Mar 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: Yes. Attackers have exploited CVE-2021-22681 in the wild since at least 5 Mar 2026.

Affected product: Rockwell Automation Studio 5000 Logix Designer, RSLogix 5000, Logix Controllers. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2021-22681/ (Markdown: https://insights.sbomify.com/CVE-2021-22681/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-22681
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-22681
- OSV: https://osv.dev/vulnerability/CVE-2021-22681

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From sbomify Insights: https://insights.sbomify.com/CVE-2021-22681/
Summaries are generated and may contain mistakes; the official description above is the record.