CISA 2026-09-01

Rockwell Automation ControlLogix, CompactLogix, CompactLogix 5480, GuardLogix, Compact GuardLogix

CVE-2021-42260

Machine-generated analysis · WAYSCloud LLM

ControlLogix, CompactLogix, GuardLogix and Compact GuardLogix controllers with firmware below 34.015 (and related patch levels) are vulnerable to a denial-of-service condition. The flaw can trigger a major non-recoverable fault that requires a program download or a stage-2 reset to recover.

Context

The advisory concerns Rockwell Automation ControlLogix, CompactLogix, CompactLogix 5480, GuardLogix and Compact GuardLogix controllers. It reports a potential denial-of-service vulnerability (CVE-2021-42260) that can be triggered by crafted data, potentially causing a major non-recoverable fault. Recovery for safety-rated controllers requires a program download, while non-safety controllers need a stage-2 reset.

Operator considerations

Check: Verify that controller firmware versions are not below the listed vulnerable releases.
Isolate: Segment or restrict network access to vulnerable controllers until they are remediated.
Log: Monitor controller logs for major non-recoverable fault events or unexpected resets.

From Cybersecurity and Infrastructure Security Agency ↗

The following versions of Rockwell Automation ControlLogix, CompactLogix, CompactLogix 5480, GuardLogix, Compact GuardLogix are affected:

ControlLogix 5580

Read the full advisory on CISA →