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

criticalCVE-2021-42260

View CSAF Summary The following versions of Rockwell Automation ControlLogix, CompactLogix, CompactLogix 5480, GuardLogix, Compact GuardLogix are affected: ControlLogix 5580 <34.015, <35.014, <36.013, <37.011 (CVE-2021-42260, CVE-2021-42260, CVE-2021-42260, CVE-2021-42260) GuardLogix 5580 <34.015, <35.014, <36.013, <37.011 (CVE-2021-42260, CVE-2021-42260, CVE-2021-42260, CVE-2021-42260) CompactLogix 5380 <34.015, <35.014, <36.013, <37.011 (CVE-2021-42260, CVE-2021-42260, CVE-2021-42260, CVE-2021-42260) Compact GuardLogix 5380 <34.015, <35.014, <36.013, <37.011 (CVE-2021-42260, CVE-2021-42260, CVE-2021-42260, CVE-2021-42260) CompactLogix 5480 <34.015, <35.014, <36.013, <37.011 (CVE-2021-42260, CVE-2021-42260, CVE-2021-42260, CVE-2021-42260) CVSS Vendor Equipment Vulnerabilities v3 7.5 Rockwell Automation Rockwell Automation ControlLogix, CompactLogix, CompactLogix 5480, GuardLogix, Compact GuardLogix Loop with Unreachable Exit Condition ('Infinite Loop') Background Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: United States Vulnerabilities Expand All + CVE-2021-42260 A potential denial of service vulnerability exists in the affected products and can be triggered via corrupt crafted data. This could result in a major nonrecoverable fault (MNRF). A program download is required to recover safety controllers. For non-safety controllers, a stage 2 reset is required to recover. View CVE Details Affected Products Rockwell Automation ControlLogix, CompactLogix, CompactLogix 5480, GuardLogix, Compact GuardLogix Vendor: Rockwell Automation Product Version: Rockwell Automation ControlLogix 5580 <34.015, Rockwell Automation ControlLogix 5580 <35.014, Rockwell Automation ControlLogix 5580 <36.013, Rockwell Automation ControlLogix 5580 <37.011, Rockwell Automation GuardLogix 5580 <34.015, Rockwell Automation GuardLogix 5580 <35.014, Rockwell Automation GuardLogix 5580 <36.013, Rockwell Automation GuardLog

CSIRTS triage

vendor: Rockwell Automation product: ControlLogix, CompactLogix, CompactLogix 5480, GuardLogix, Compact GuardLogixOtheraffected: ControlLogix 5580 <34.015, <35.014, <36.013, <37.011; GuardLogix 5580 <34.015, <35.014, <36.013, <37.011; CompactLogix 5380 <34.015, <35.014, <36.013, <37.011; Compact GuardLogix 5380 <34.015, <35.014

What: CVE-2021-42260 affects multiple Rockwell Automation PLC models across firmware versions.
Who is affected: Industrial control systems running the affected Rockwell Automation PLC models worldwide are at risk.
Urgency: Critical urgency given the CVSS 7.5 score and impact on critical infrastructure.
Action: Upgrade firmware to versions 34.015 or later, 35.014 or later, 36.013 or later, or 37.011 or later as appropriate for each device.

AI-assisted analysis generated from the source advisory — verify against the original.

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Details

Source: CISA Cybersecurity Advisories (US · national-cert · site)
Severity: critical
Published: 2026-09-01
Exploitation: Not in CISA KEV at last sync

Original advisory: https://www.cisa.gov/news-events/ics-advisories/icsa-26-244-05

Exploitation outlook

EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.

Moderate exploitation riskCVE-2021-422603.3% 30-day exploitation probability. Patch within normal cadence, watch for KEV listing. Riskier than 88% of all EPSS-scored CVEs.

Referenced CVEs

CVE	CSIRTS overview	External
CVE-2021-42260	coverage & exploitation status	NVD · CVE.org

Same CVEs, other sources

How other CERTs, PSIRTs and databases cover the vulnerabilities in this advisory.

medium[NEW] [medium] Rockwell Automation ControlLogix 5580, CompactLogix 5380, and CompactLogix 5480: Multiple vulne…cert-bund

Recent advisories for Rockwell Automation ControlLogix

A cluster of recent advisories against the same product widens the attack surface — attackers routinely chain freshly published CVEs on one product, so review these together.

medium[NEW] [medium] Rockwell Automation ControlLogix 5580, CompactLogix 5380, and CompactLogix 5480: Multiple vulne…cert-bund · 2026-09-02
criticalRockwell Automation CompactLogix 5380 ControlLogix 5580 / 1756-EN4TR Communications Modulecisa · 2026-07-30
high[NEW] [high] Rockwell Automation CompactLogix and ControlLogix: Multiple vulnerabilitiescert-bund · 2026-07-17
unknownRockwell Automation CompactLogix, ControlLogix, Compact GuardLogix and GuardLogixcisa · 2026-07-16