CVE-2026-9622: CWE-191 Integer underflow (wrap or wraparound) in Rockwell Automation RSLinx Classic®
Description
A denial-of-service security issue exists within RSLinx® Classic. A crafted CIP packet targeting the Forward Close service can cause the RSLinx® Classic service to crash, requiring a restart of the service to recover.
CVSS v4.0
Score 8.7high
Affected software
Rockwell Automation
RSLinx Classic®
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability in RSLinx Classic arises from an integer underflow condition when processing a specially crafted CIP packet aimed at the Forward Close service. Exploiting this flaw causes the RSLinx Classic service to crash, resulting in denial of service that disrupts normal operation until the service is manually restarted. The CVSS 4.0 base score is 8.7, indicating a high impact with network attack vector, no privileges or user interaction required, and high impact on availability.
Potential Impact
Successful exploitation causes a denial-of-service condition by crashing the RSLinx Classic service, requiring manual service restart to recover. This disrupts availability of the affected service but does not indicate confidentiality or integrity impacts.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. No official fix or workaround information is currently available. Until a patch is released, monitoring for suspicious CIP packets and limiting network exposure of RSLinx Classic services may reduce risk.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Rockwell
- Date Reserved
- 2026-05-26T17:18:22.609Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a96d8b2acd9273b49c6bfa2
Added to database: 09/01/2026, 13:52:50 UTC
Last enriched: 09/07/2026, 14:43:32 UTC
Last updated: 10/15/2026, 18:48:26 UTC
Views: 76
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