CVE-2026-51540
Integer underflow in OpENer SendUnitData leads to remote memory corruption and potential device takeover.
Is CVE-2026-51540 being exploited?
Not confirmed. CVE-2026-51540 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 0.42% probability of exploitation in the next 30 days.
How severe is CVE-2026-51540?
CVE-2026-51540 is rated Critical with a CVSS score of 9.8. 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-2026-51540?
Yes. A fix has been recorded for CVE-2026-51540. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-51540 affect?
CVE-2026-51540 affects OpENer 2.3.0 (master up to commit 76b95cf), Embedded 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-2026-51540?
Isolate EtherNet/IP devices; block/inspect SendUnitData from untrusted nets; apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Crafted EtherNet/IP SendUnitData packets cause integer underflow -> memory corruption enabling remote code execution or device crash.
Immediate action required