CVE-2026-71256
nanoMODBUS out-of-bounds read
- Published5 Aug 2026
Description
nanoMODBUS through v1.23.0 contains an out-of-bounds stack read leading to a wild-pointer write in nmbs_read_device_identification_basic / recv_read_device_identification_res in nanomodbus.c. A fixed 3-element stack array order[3] = {0,1,2} maps object IDs to buffer indices. The server-supplied object_id field (0-255, read directly from the wire) is used without any bounds check as buf_index = order[object_id].
CVSS 3.1 breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HRemediation
No fixed version is recorded in the NVD data. Check the vendor advisory for the latest guidance.
References
Related CVEs
Recent high-severity vulnerabilities sharing a weakness type.
Frequently asked
Is CVE-2026-71256 being actively exploited?
CVE-2026-71256 is not in the CISA KEV catalog. Its EPSS exploit probability is 0.55%.
How severe is CVE-2026-71256?
CVE-2026-71256 has a CVSS 3.1 base score of 9.8, rated critical. EPSS estimates a 0.55% probability of exploitation.
How do I fix CVE-2026-71256?
Apply the vendor's patch or advisory guidance, then verify no affected versions remain across your devices.
How Secuno handles this
Secuno correlates vulnerabilities like CVE-2026-71256 against the real software inventory on every managed device, every day. Rather than a static severity, each match is scored in context: exploit availability, EPSS, the asset's exposure, and business criticality decide where it lands in the queue. If an affected version is present anywhere across your portfolio, it surfaces automatically with a prioritised remediation path.
Data from the NVD, CISA KEV catalog and FIRST EPSS. CVSS 3.1 base score shown where available.