CVE-2026-51536
Stack buffer overflow in OpENer CIP packet parsing enabling RCE or crash
Is CVE-2026-51536 being exploited?
Not confirmed. CVE-2026-51536 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 0.49% probability of exploitation in the next 30 days.
How severe is CVE-2026-51536?
CVE-2026-51536 is rated Critical with a CVSS score of 9.1. 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-2026-51536?
Yes. A fix has been recorded for CVE-2026-51536. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-51536 affect?
CVE-2026-51536 affects OpENer 2.3.0 (commit 76b95cf), Devices using OpENer EtherNet/IP stack. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-51536?
Block/inspect/segment CIP traffic, apply vendor patch when released, monitor ICS network logs
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Crafted CIP (EtherNet/IP) packets can trigger a stack buffer overflow in DecodePaddedEPath, causing crashes or potential remote code execution on affected devices.
Immediate action required