Remotely triggerable, unauthenticated flaw in a widely used EtherNet/IP stack for industrial devices that can disrupt OT operations across sectors.
CVE-2026-51537
Remote out-of-bounds read in OpENer 2.3.0 Connection Manager via malformed ForwardOpen
Is CVE-2026-51537 being exploited?
Not confirmed. CVE-2026-51537 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 0.48% probability of exploitation in the next 30 days.
How severe is CVE-2026-51537?
CVE-2026-51537 is rated Critical. 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-2026-51537?
Yes. A fix has been recorded for CVE-2026-51537. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-51537 affect?
CVE-2026-51537 affects EIPStackGroup OpENer 2.3.0, Devices using OpENer EtherNet/IP stack (PLCs, controllers). Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-51537?
Isolate EtherNet/IP devices, block ENIP traffic at network edges, apply vendor/OpENer patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote unauthenticated OOB read causing crashes/DoS and potential data disclosure; may enable follow-on exploitation of EtherNet/IP devices.
Immediate action required