Rockwell Automation RSLinx Classic

September 1, 2026 · CISA (US-CERT) · Severity: CRITICAL

View CSAF Summary Successful exploitation of these vulnerabilities could allow an attacker to cause a denial-of-service condition on the affected product. The following versions of Rockwell Automation RSLinx Classic are affected: RSLinx Classic <=4.50 (CVE-2026-9621, CVE-2026-9622, CVE-2026-9624, CVE-2026-9625) CVSS Vendor Equipment Vulnerabilities v3 8.6 Rockwell Automation Rockwell Automation RSLinx Classic Integer Overflow or Wraparound, Integer Underflow (Wrap or Wraparound), Buffer Copy without Checking Size of Input ('Classic Buffer Overflow') Background Critical Infrastructure Sectors: Critical Manufacturing Countries/Areas Deployed: Worldwide Company Headquarters Location: United States Vulnerabilities Expand All + CVE-2026-9621 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. View CVE Details Affected Products Rockwell Automation RSLinx Classic Vendor:Rockwell Automation Product Version:Rockwell Automation RSLinx Classic: <=4.50 Product Status:known_affected Remediations Vendor fixRockwell Automation has corrected the vulnerabilities in RSLinx Classic version 4.60. MitigationUsers using the affected software, who are not able to upgrade to one of the corrected versions, should use Rockwell Automation's security best practices https://support.rockwellautomation.com/app/answers/answer_view/a_id/1085012/loc/en_US#__highlight.https://support.rockwellautomation.com/app/answers/answer_view/a_id/1085012/loc/en_US#__highlight MitigationFor more information, see Rockwell Automation Security Advisories: https://www.rockwellautomation.com/en-us/trust-center/security-advisories.html.https://www.rockwellautomation.com/en-us/trust-center/security-advisories.html Relevant CWE: CWE-190 Integer Overflow or Wraparound Metrics CVSS...