Denial-of-Service Vulnerability in RSLinx Classic by Rockwell Automation
CVE-2026-9621

9.2CRITICAL

Key Information:

Vendor

Rockwell Automation
Status
Rslinx Classic®
Vendor
CVE Published:
1 September 2026

What is CVE-2026-9621?

A denial-of-service security issue exists in RSLinx® Classic due to improper handling of specially crafted CIP packets. An attacker can exploit this vulnerability by sending a malformed packet to the service, causing it to crash. This requires a manual restart of the RSLinx® Classic service to restore functionality. Organizations using this service must implement mitigations and monitor their systems to avoid disruptions caused by this security concern.

Affected Version(s)

RSLinx Classic® V4.50 and prior

References

https://www.rockwellautomation.com/en-us/trust-center/sec...

CVSS V4

Score:
9.2
Severity:
CRITICAL
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

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