CVE-2026-9621 PUBLISHED

RSLinx Classic® - Multiple Vulnerabilities

Assigner: Rockwell
Reserved: 26.05.2026 Published: 01.09.2026 Updated: 01.09.2026

A denial-of-service security issue exists within RSLinx® Classic. The security issue stems from improper handling of a malformed packet. A crafted CIP packet can cause the RSLinx® Classic service to crash, requiring a restart of the service to recover

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:H
CVSS Score: 9.2

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	High
Privileges Required	None
User Interaction	None

CVSS 4.0

Product Status

Vendor	Rockwell Automation
Product	RSLinx Classic®
Versions	Default: unaffected Version V4.50 and prior is affected

References

https://www.rockwellautomation.com/en-us/trust-center/security-advisories/advisory.SD1794.html

Problem Types

CWE-190 Integer overflow or wraparound CWE