CVE-2026-71255
Modbus client library OOB write allows memory corruption via crafted server response.
Is CVE-2026-71255 being exploited?
Not confirmed. CVE-2026-71255 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 0.22% probability of exploitation in the next 30 days.
How severe is CVE-2026-71255?
CVE-2026-71255 is rated High with a CVSS score of 8.6. 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-2026-71255?
Not known from our data. No patch reference has been recorded for CVE-2026-71255, which is not the same as no patch existing — a fix may have shipped without a tagged reference, or after this record was written. The vendor advisory is the only authority on whether a fix exists, and mitigations may be available regardless.
What does CVE-2026-71255 affect?
CVE-2026-71255 affects nanoMODBUS <= 1.23.0, Embedded/IoT devices using nanoMODBUS client, Industrial Modbus client implementations. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-71255?
Block untrusted Modbus servers, restrict Modbus client network access, and apply vendor patch when available.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
A malicious Modbus server can trigger an out-of-bounds NUL write, causing crashes, memory corruption, or potential remote code execution on clients.
Immediate action required
- affected<= 1.23.0
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.