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CVE-2026-9622

8.7
High
EPSS 0.31%Patch availableSep 1, 2026

DoS in RSLinx Classic via crafted CIP Forward Close packet crashes service

common questions

Is CVE-2026-9622 being exploited?

Not confirmed. CVE-2026-9622 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.31% probability of exploitation in the next 30 days.

How severe is CVE-2026-9622?

CVE-2026-9622 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2026-9622?

Yes. A fix has been recorded for CVE-2026-9622. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-9622 affect?

CVE-2026-9622 affects Rockwell Automation RSLinx Classic, Systems using CIP / EtherNet/IP, Industrial control networks with RSLinx service. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-9622?

Apply vendor update, segment/block CIP (EtherNet/IP), monitor and restart RSLinx service as needed

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Rockwell Automation RSLinx ClassicSystems using CIP / EtherNet/IPIndustrial control networks with RSLinx service
impact

Remote denial-of-service: crafted CIP Forward Close packet crashes the RSLinx Classic service, interrupting controller communications and potential OT process disruption.

action required

Patch when possible

affected versions
Rockwell Automation RSLinx Classic®
  • affectedV4.50 and prior

As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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