CVE-2026-71256: critical vulnerability in debevv nanoMODBUS
nanoMODBUS Client-Side Out-of-Bounds Read Leading to Wild-Pointer Write via object_id
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28Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 9.8epss 0.6%
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/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected products
debevv · nanoMODBUSRelated CVEs — debevv nanoMODBUS
In the same product, most dangerous first.
CVE-2026-71254CRITICALnanoMODBUS Server-Side Out-of-Bounds Write in handle_read_file_record()EPSS 0.6%CVE-2026-54410HIGHnanoMODBUS Off-by-One Buffer Overflow in recv_msg_header() via Crafted MBAP Length FieldEPSS 0.5%CVE-2026-71255HIGHnanoMODBUS Client-Side Out-of-Bounds Write via object_length in recv_read_device_identification_res()EPSS 0.4%