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

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 Vendor fixRockwell Automation recommends users update to firmware version 34.015 and later. Vendor fixRockwell Automation recommends users update to firmware version 35.014 and later. Vendor fixRockwell Automation recommends users update to firmware version 36.013 and later.

Vendor fixRockwell Automation recommends users update to firmware version 37.011 and later. MitigationCustomers using the affected software who are not able to upgrade to one of the corrected versions should use Rockwell Automation's security best practices.

Relevant CWE: CWE-835 Loop with Unreachable Exit Condition ('Infinite Loop') Metrics CVSS Version Base Score Base Severity Vector String 3.1 7.5 HIGH CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H 4.0 8.7 HIGH CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N Acknowledgments Rockwell Automation reported this vulnerability to CISA Legal Notice and Terms of Use This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).

Recommended Practices CISA recommends users take defensive measures to minimize the risk of exploitation of these vulnerabilities. Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet. Locate control system networks and remote devices behind firewalls and isolating them from business networks.

When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices. CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.

CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.

CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets. Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.

Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents. CISA also recommends users take the following measures to protect themselves from social engineering attacks: Do not click web links or open attachments in unsolicited email messages.

Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams. Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks. No known public exploitation specifically targeting these vulnerabilities has been reported to CISA at this time.

Revision History Initial Release Date: 2026-09-01 Date Revision Summary 2026-09-01 1 Initial republication of Rockwell Automation advisory Legal Notice and Terms of Use