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CVE-2026-71256— nanoMODBUS Client-Side Out-of-Bounds Read Leading to Wild-Pointer Write via object_id

Quick assessment

Affected
debevv nanoMODBUS
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Valerio De Benedetto nanoMODBUS是Valerio De Benedetto个人开发者的一款MODBUS通信协议实现库。 Valerio De Benedetto nanoMODBUS 1.23.0及之前版本存在缓冲区错误漏洞，该漏洞源于nmbs_read_device_identification_basic()/recv_read_device_identification_res()函数中未对object_id字段进行边界检查，导致越界栈读取和野指针写入，可能造成任意地址

CVSS 9.8 · Critical EPSS 0.55% · P44

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 1

VendorProduct Version RangeStatus
debevv nanoMODBUS ≤ 1.23.0 affected
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I. Basic Information for CVE-2026-71256

Vulnerability Information
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Vulnerability Title
nanoMODBUS Client-Side Out-of-Bounds Read Leading to Wild-Pointer Write via object_id
Source: CVE Program / CVE List V5
Vulnerability Description
nanoMODBUS through v1.23.0 contains an out-of-bounds stack read leading to a wild-pointer write in nmbs_read_device_identification_basic / recv_read_device_identification_res in nanomodbus.c. A fixed 3-element stack array order[3] = {0,1,2} maps object IDs to buffer indices. The server-supplied object_id field (0-255, read directly from the wire) is used without any bounds check as buf_index = order[object_id].
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存读
Source: CVE Program / CVE List V5
Vulnerability Title
Valerio De Benedetto nanoMODBUS 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Valerio De Benedetto nanoMODBUS是Valerio De Benedetto个人开发者的一款MODBUS通信协议实现库。 Valerio De Benedetto nanoMODBUS 1.23.0及之前版本存在缓冲区错误漏洞，该漏洞源于nmbs_read_device_identification_basic()/recv_read_device_identification_res()函数中未对object_id字段进行边界检查，导致越界栈读取和野指针写入，可能造成任意地址
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
debevv nanoMODBUS 0 ~ 1.23.0 -

II. Public POCs for CVE-2026-71256

# POC Description Source Link Shenlong Link
AI-Generated POC Premium
Qwen3.6-35B-A3B · 7956 chars
Pro+ exclusive includes:
Vulnerability reproduction recording (real sandbox build + trigger, exclusive)
In-depth vulnerability mechanism
Trigger conditions & impact
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Exploit chain & mitigation
POC zip download
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III. Intelligence Information for CVE-2026-71256

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Other References for CVE-2026-71256 (1)

Same Patch Batch · debevv · 2026-08-05 · 3 CVEs total

CVE-2026-71254 9.8 CRITICAL nanoMODBUS Server-Side Out-of-Bounds Write in handle_read_file_record()
CVE-2026-71255 8.6 HIGH nanoMODBUS Client-Side Out-of-Bounds Write via object_length in recv_read_device_identific

IV. Related Vulnerabilities

Same product: nanoMODBUS
Same vendor: debevv
Same weakness: CWE-125

V. Comments for CVE-2026-71256

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