CVE-2026-71256

9.8 CRITICALpublic exploit available

Published 2026-08-05 · Updated 2026-08-10

AI risk analysis

Summary: The flaw involves an out-of-bounds stack read in nanoMODBUS v1.23.0, allowing a wild-pointer write that can lead to severe system vulnerabilities.
Exploitability: Exploitation is relatively straightforward given the direct use of unbounded object_id without validation, requiring only a crafted packet with an object_id value greater than 2.
Blast radius: If exploited, this flaw could result in arbitrary code execution or data corruption on affected systems, leading to significant operational disruptions.
Prioritized remediation: Update to the latest version of nanoMODBUS that includes the necessary bounds checking and security patches.

rcestack-overflowmodbusics

Analysis generated locally by qwen2.5:7b-instruct (no data left the box). AI-assisted — verify against primary sources before acting.

NVD 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 vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Weaknesses

CWE-125

Public exploit & PoC references

All references

Source data: NVD (nvd.nist.gov), public domain. Exploit-DB.ai adds local AI analysis for defensive use only.