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CVE-2026-71255Suited to automated attack · CISA

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

CVSS score

8.6

EPSS probability

%0.4

Risk score

0.0

Published

2 mo ago

Patch status has not yet been verified

Resmî kaynaklarda yeterli kanıt bulunamadı. Bu sonuç “yama yok” anlamına gelmez.

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Vulnerability description

CVE AI research

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DayBreach AI Explanation

Verified against sources

High-impact out-of-bounds write in nanoMODBUS v1.23.0 enables memory corruption and potential privilege escalation.

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%53

Short explanation

CVE-2026-71255 in nanoMODBUS v1.23.0 allows client-side out-of-bounds write due to insufficient validation of object_length. CVSS 8.2 indicates high severity. No public exploit or active exploitation confirmed. Patch status is UNKNOWN due to lack of vendor advisories.

Why does it matter?

This vulnerability allows remote attackers to trigger memory corruption and potentially gain root access. No active exploitation is confirmed, but high CVSS score and memory corruption risk make it a critical concern for systems using nanoMODBUS.

What should be done?

  • Apply vendor patch if available
  • Upgrade to a version beyond 1.23.0 if vendor provides a fixed version
  • Follow official vendor advisory without assuming a version
Note on uncertainty

The sources give limited detail on some technical conditions. Review the chain of evidence below before deciding how to act.

Chain of evidence and sources3 verified claims

CVE-2026-71255, nanoMODBUS 1.23.0 ve altında, recv_read_device_identification_res() fonksiyonunda object_length'nin buffers_length ile karşılaştırılmaması nedeniyle istemci tarafında sınırlı yazma izni sağlar ve komut hatası ile root yetkileri ele geçirilmesine neden olabilir.

Açık, CVSS 3.1 puanı 8.2 ile yüksek önemde ve uzak istismar potansiyeline sahiptir.

Kullanıcı tarafında istismar veya aktif istismar doğrulanmamıştır; yama durumu bilinmiyor çünkü üretici açıklaması veya resmi düzeltme yoktur.

Show the technical text from the sources

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.

CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H

CWE: CWE-787

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-2026-71255 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1debevvnanoMODBUS View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

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.

SCOREVERSIONSEVERITYVECTORSOURCE
8.6CVSS V3_1HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:HCVE CNA
8.6CVSS V31HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:HNVD

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

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-2026-71255 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-2026-71255 weaknesses.

Attack Vector and Accessibility

ExposureAğ üzerinden
PermissionsGerekmiyor
UserGerekmiyor

Official Sources and Advisories

CVSS Vector Radar Chart

8.6 / 10
Attack VectorNetworkComplexityLowPrivilegesNoneUser Interact.NoneConfidentialityLowIntegrityNoneAvailabilityHigh

Vulnerability Scoring Details

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H
Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone required
User InteractionNone required
Confidentiality (Gizlilik)Low
Integrity (Bütünlük)None
Availability (Erişilebilirlik)High

Yama durumu bilinmiyor

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Weakness Type (CWE & CAPEC)

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