# CVE-2026-54410

## Summary

- **CVE ID:** CVE-2026-54410
- **Severity:** HIGH
- **CVSS Score:** 9 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:H/SC:N/SI:N/SA:N/E:P/AU:Y)
- **CWE:** CWE-193, CWE-787
- **Published:** Jun 14, 2026
- **Last Modified:** Aug 10, 2026

## Description

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. The overflow corrupts the adjacent buffer-index field of the nanoMODBUS state structure, resulting in denial of service through invalid memory accesses and, on bare-metal and RTOS targets without memory protection, one-byte information disclosure and writes to unintended register addresses on the Write Multiple Registers (FC16) handler path.

## Affected Products

- debevv — nanoMODBUS (0)

## References

- [CNA](https://github.com/debevv/nanoMODBUS)
- [CNA](https://github.com/debevv/nanoMODBUS/blob/v1.23.0/nanomodbus.c#L369)
- [CNA](https://cwe.mitre.org/data/definitions/193.html)
- [CNA](https://cwe.mitre.org/data/definitions/787.html)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.54%
- **EPSS Percentile:** 43.7

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-10._