Affects Rockwell Automation Logix PLC family used across industrial sectors; can cause nonrecoverable faults and stop production, posing cross-industry OT disruption risk.
CVE-2026-9637
DoS in Rockwell Logix PLCs via CIP messages causing nonrecoverable fault.
Is CVE-2026-9637 being exploited?
Not confirmed. CVE-2026-9637 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-2026-9637?
CVE-2026-9637 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-2026-9637?
Yes. A fix has been recorded for CVE-2026-9637. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-9637 affect?
CVE-2026-9637 affects Rockwell Automation Logix family, ControlLogix, CompactLogix, GuardLogix, and 1 further product or version. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-9637?
Apply vendor patch, block/untrusted CIP traffic, isolate controllers from IT networks.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote denial-of-service: crafted CIP/EtherNet/IP messages trigger a major nonrecoverable fault (MNRF), halting controllers and requiring power-cycle recovery.
Immediate action required
- affectedV33 and prior, V34.011-V34.014, V35.011-V35.013, V36.011-V36.012
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.