CVE-2026-9653 PUBLISHED

1756-EN2, 1756-EN3, and 1756-ENBT - Denial of Service via CIP Connection ID

Assigner: Rockwell
Reserved: 26.05.2026 Published: 14.07.2026 Updated: 14.07.2026

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.

Metrics

CVSS 4.0

CVSS Vector: 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
CVSS Score: 8.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	None	Confidentiality	None
Attack Complexity	Low	Integrity	None	Integrity	None
Attack Requirements	None	Availability	High	Availability	None
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Rockwell Automation
Product	1756-EN2, 1756-EN3
Versions	Default: unaffected Version 12.001 and before is affected

Vendor	Rockwell Automation
Product	1756-ENBT
Versions	Default: unaffected Version 6.006 is affected

References

https://www.rockwellautomation.com/en-us/trust-center/security-advisories/advisory.SD1780.html

Problem Types

CWE-354 Improper validation of integrity check value CWE