Vulnerability · Published Aug 5, 2026 · Assigned by TuranSec

CVE-2026-71255nanoMODBUS Client-Side Out-of-Bounds Write via object_length in recv_read_device_identification_res()

High 8.6

In plain English

A high-severity out-of-bounds write in nanoMODBUS from debevv. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities).

Severity (CVSS 3.1)8.6High

Exploit odds (30 days)0.4%top 67.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side recv_read_device_identification_res function (FC 0x2B/MEI 0x0E, Read Device Identification) in nanomodbus.c. The server-supplied object_length field (0-246) is validated only against the remaining PDU size (res_size_left) and is never validated against the caller-supplied buffers_length parameter.

Affected products (as reported)

Vendor	Product	Versions
debevv	nanoMODBUS	0 – through 1.23.0

Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

References

https://github.com/debevv/nanoMODBUS third-party-advisory
https://github.com/debevv/nanoMODBUS/blob/master/nanomodbus.c third-party-advisory