Rockwell Automation 1756-EN2, 1756-EN3, and 1756-ENBT

View CSAF
Summary
Successful exploitation of this vulnerability could allow an attacker to cause a denial-of-service condition.
The following versions of Rockwell Automation 1756-EN2, 1756-EN3, and 1756-ENBT are affected:

1756-EN3 <=V12.001 (CVE-2026-9653)
1756-EN2 <=V12.001 (CVE-2026-9653)
1756-ENBT V6.006 (CVE-2026-9653)





CVSS
Vendor
Equipment
Vulnerabilities




v3 7.5
Rockwell Automation
Rockwell Automation 1756-EN2, 1756-EN3, and 1756-ENBT Improper Validation of Integrity Check Value




Background

Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: United States


Vulnerabilities

Expand All +

CVE-2026-9653

A denial-of-service security issue exists across all the 1756-EN2, EN3, and ENBT communication module due to improper validation of CIP Implicit Connection
packets. An attacker on the network can exploit this by sending crafted packets to continuously disrupt device connections, though device connections will recover immediately after.
View CVE Details

Affected Products
Rockwell Automation 1756-EN2, 1756-EN3, and 1756-ENBT

Vendor:Rockwell Automation
Product Version:Rockwell Automation 1756-EN3: <=V12.001, Rockwell Automation 1756-EN2: <=V12.001, Rockwell Automation 1756-ENBT: V6.006 Product Status:known_affected


Remediations
Vendor fixRockwell Automation recommends users take the following actions: 1756-EN3: Update to V12.002
Vendor fix1756-EN2: Update to V12.002 Vendor fix1756-ENBT: Product is discontinued, fix is unavailable

Relevant CWE: CWE-354 Improper Validation of Integrity Check Value

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

Tyler Lentz of Idaho National Laboratory 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 this vulnerability. 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 this vulnerability has been reported to CISA at this time.

Revision History

Initial Release Date: 2026-07-16




Date
Revision
Summary




2026-07-16
1
Initial Publication




Legal Notice and Terms of Use

https://www.cisa.gov/news-events/ics-advisories/icsa-26-197-02

2026-07-16 12:00 UTC

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