nanoMODBUS Client-Side Out-of-Bounds Read Leading to Wild-Pointer Write via object_id
CVSS score
9.8
EPSS probability
%0.6
Risk score
0.1
Published
2 mo ago
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
1
Source agreement
Tam uyum
Evidence confidence
%50
Short explanation
CVE-2026-71256 in nanoMODBUS v1.23.0 allows client-side out-of-bounds read leading to wild-pointer write via unbounded object_id. CVSS 8.1 severity. No known patch. Active exploitation not confirmed.
This vulnerability enables remote attackers to write arbitrary data to memory via a client-side exploit, posing high risk to system integrity and confidentiality. No known patch; mitigation requires vendor action or service restriction.
What should be done?
- Apply vendor patch if available; otherwise, disable or restrict Modbus client usage until a fix is released
The sources give limited detail on some technical conditions. Review the chain of evidence below before deciding how to act.
Chain of evidence and sources
CVE-2026-71256, nanoMODBUS 1.23.0'ya kadar olan sürümde, object_id kullanımında sınırsızlık nedeniyle istisnai bellek okuma ve wild-pointer yazma olur. CVSS 8.1 şiddetindedir.
nanoMODBUS'da nmbs_read_device_identification_basic() ve recv_read_device_identification_res() fonksiyonlarında, sunucudan gelen object_id (0-255) sınırsız kontrol olmadan kullanılır.
Zayıf bir Modbus sunucusu, sınır dışı okuma tetikleyebilir ve sunucu kontrolüyle belirli bir bellek adresine istisnai bir işaret yazabilir.
Show the technical text from the sources
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].
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CWE: CWE-125
Explanation produced with the local qwen3:4b-instruct model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-71256 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
| ID | VENDOR | PRODUCT | ACTION |
|---|---|---|---|
| 1 | debevv | nanoMODBUS | View |
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 9.8 | CVSS V3_1 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | CVE CNA |
| 9.8 | CVSS V31 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
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Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-71256 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-71256 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
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