Answer in brief
CVE-2026-9621 records a Critical severity (CVSS 9.2) vulnerability in RSLinx Classic® - Multiple Vulnerabilities. The current sources do not mark it as known exploited. The current feed maps Rockwell Automation/RSLinx Classic® (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 9.2. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Rockwell Automation/RSLinx Classic® (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Rockwell Automation/RSLinx Classic®generic | V4.50 and prior | Not reported |
Published upstream
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 1, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 1, 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
Quoted source text, attributed separately from HOL analysis.