debevv nanoMODBUS up to 1.23.0 Client Receive Logic nanomodbus.c recv_read_device_identification_res buffers_length out-of-bounds write

Summaryinfo

A vulnerability labeled as critical has been found in debevv nanoMODBUS up to 1.23.0. This impacts the function recv_read_device_identification_res of the file nanomodbus.c of the component Client Receive Logic. Such manipulation of the argument buffers_length leads to out-of-bounds write. This vulnerability is documented as CVE-2026-71255. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in debevv nanoMODBUS up to 1.23.0 and classified as critical. Affected by this issue is the function recv_read_device_identification_res of the file nanomodbus.c of the component Client Receive Logic. The manipulation of the argument buffers_length with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

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. After copying data with strncpy(buffers_out[buf_index], str, buffers_length), the code unconditionally writes a NUL terminator at buffers_out[buf_index][object_length]. When a malicious or compromised Modbus server sends a response with object_length greater than or equal to the client's buffers_length, this NUL write lands past the end of the caller-provided buffer, corrupting adjacent stack or heap memory on the client.

The advisory is available at github.com. This vulnerability is handled as CVE-2026-71255 since 08/05/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 08/05/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Vendor

• debevv

Name

• nanoMODBUS

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23.0

CPE 2.3info

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CPE 2.2info

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