CVE-2026-71254

9.8 CRITICALpublic exploit available

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

AI risk analysis

Summary: The flaw allows an attacker to perform out-of-bounds writes by manipulating Modbus requests, leading to potential code execution or data corruption.
Exploitability: Exploitation is moderately difficult requiring knowledge of Modbus protocol and specific request crafting; preconditions include access to the affected nanoMODBUS server.
Blast radius: If exploited, this could lead to significant damage including system compromise or operational disruption in industrial control systems.
Prioritized remediation: Update to the latest version of nanoMODBUS that addresses this vulnerability or apply a patch if available.

modbusicswrite-attackpatch-recommended

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 write in the Modbus server-side handle_read_file_record function (FC 0x14, Read File Record) in nanomodbus.c. The function validates that the total request size does not exceed 245 bytes and that each sub-request's record_length is at most 124, but it never validates the CUMULATIVE response size across all sub-requests before processing them.

CVSS vector

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

Weaknesses

CWE-787

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.