CVE-2026-71255

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Source
https://cve.org/CVERecord?id=CVE-2026-71255
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-71255.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-71255
Published
2026-08-05T11:44:21.097Z
Modified
2026-08-07T21:55:20.137091Z
Severity
  • 8.6 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H CVSS Calculator
Summary
nanoMODBUS Client-Side Out-of-Bounds Write via object_length in recv_read_device_identification_res()
Details

nanoMODBUS through v1.23.0 contains an out-of-bounds write in the Modbus client-side recvreaddeviceidentificationres() function (FC 0x2B/MEI 0x0E, Read Device Identification) in nanomodbus.c. The server-supplied objectlength field (0-246) is validated only against the remaining PDU size (ressizeleft) and is never validated against the caller-supplied bufferslength parameter. After copying data with strncpy(buffersout[bufindex], str, bufferslength), the code unconditionally writes a NUL terminator at buffersout[bufindex][objectlength]. When a malicious or compromised Modbus server sends a response with objectlength greater than or equal to the client's bufferslength, this NUL write lands past the end of the caller-provided buffer, corrupting adjacent stack or heap memory on the client.

Database specific 
{
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/71xxx/CVE-2026-71255.json",
    "cna_assigner": "TuranSec",
    "cwe_ids": [
        "CWE-787"
    ]
}
References

Affected packages

Git / github.com/debevv/nanomodbus

Affected ranges

Type
GIT
Repo
https://github.com/debevv/nanomodbus
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Fixed
91d6782930ee263bc760f27b0cbc5b82773c5f0d
Database specific 
{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "1.23.0"
        },
        {
            "fixed": "v1.23.0"
        }
    ],
    "source": [
        "AFFECTED_FIELD",
        "DESCRIPTION"
    ]
}

Affected versions

v1.*
v1.0
v1.0.0
v1.0.1
v1.1.0
v1.1.1
v1.10.0
v1.11.0
v1.12.0
v1.12.1
v1.13.0
v1.14.0
v1.14.1
v1.14.2
v1.14.3
v1.15.0
v1.16.0
v1.17.0
v1.17.1
v1.17.2
v1.17.3
v1.18.1
v1.19.0
v1.2.0
v1.2.1
v1.20.0
v1.20.1
v1.21.0
v1.22.0
v1.22.1
v1.3.0
v1.3.1
v1.4.0
v1.5.0
v1.6.0
v1.7.0
v1.8.0
v1.8.1
v1.9.0
v1.9.1

Database specific

vanir_signatures 
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        },
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        "signature_version": "v1",
        "target": {
            "file": "nanomodbus.c",
            "function": "recv_read_registers_res"
        },
        "source": "https://github.com/debevv/nanomodbus/commit/91d6782930ee263bc760f27b0cbc5b82773c5f0d",
        "signature_type": "Function"
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        "digest": {
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        "deprecated": false,
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        "signature_version": "v1",
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        "deprecated": false,
        "id": "CVE-2026-71255-c3fa9421",
        "signature_version": "v1",
        "target": {
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        "source": "https://github.com/debevv/nanomodbus/commit/91d6782930ee263bc760f27b0cbc5b82773c5f0d",
        "signature_type": "Line"
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]
vanir_signatures_modified 
"2026-08-07T21:55:20Z"
source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-71255.json"