---
id: CVE-2026-54410
title: >-
  nanoMODBUS through v1.23.0 contains an off-by-one buffer overflow in the
  recv_msg_header function of the Modbus/TCP server that allows remote
  unauthenticated attackers to write one attacker-controlled byte past the end
  of the 260-byte re…
summary: >-
  nanoMODBUS through v1.23.0 contains an off-by-one buffer overflow in the
  recv_msg_header function of the Modbus/TCP server that allows remote
  unauthenticated attackers to write one attacker-controlled byte past the end
  of the 260-byte re…
severity: high
cvss: 8.6
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H'
cwe:
  - CWE-193
  - CWE-787
published: '2026-06-14'
updated: '2026-08-10'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-54410'
references:
  - url: 'https://cwe.mitre.org/data/definitions/193.html'
    label: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
  - url: 'https://cwe.mitre.org/data/definitions/787.html'
    label: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
  - url: 'https://github.com/debevv/nanoMODBUS'
    label: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
  - url: 'https://github.com/debevv/nanoMODBUS/blob/v1.23.0/nanomodbus.c#L369'
    label: 309f9ea4-e3e9-4c6c-b79d-e8eb01244f2c
tags:
  - nvd
epss: 0.00861
epssPercentile: 0.56788
ingestedAt: '2026-08-10T12:39:46.720Z'
---

## Overview

nanoMODBUS through v1.23.0 contains an off-by-one buffer overflow in the recv_msg_header function of the Modbus/TCP server that allows remote unauthenticated attackers to write one attacker-controlled byte past the end of the 260-byte receive buffer by sending a crafted MBAP frame whose Length field is set to 255.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.