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Vulnerability record · public intelligence
CVE-2026-71256
CRITICAL

nanoMODBUS Client-Side Out-of-Bounds Read Leading to Wild-Pointer Write via object_id

Published Aug 5, 2026 · Updated Nov 3, 2026

Severity · CVSSCRITICAL · Not scored
Known exploitationNot listed
EPSS / likelihood0.55%
QFinch risk scoreNot available

Original summary

Normalized public record · Updated Nov 3, 2026

nanoMODBUS Client-Side Out-of-Bounds Read Leading to Wild-Pointer Write via object_id

Publisher and source text is retained separately from QFinch interpretation.

QFinch assessment

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].

Evidence: public source records

Affected products

Affected scope reported by the available public evidence
Affected package, product or rangeFix status
Consult the referenced vendor advisory for affected versions.Consult source advisory

Matching a version is only one part of assessing exposure. QFinch has not assessed your environment on this public page.

Remediation

Apply the vendor-supported fixed release or mitigation, then verify the affected component is no longer reachable.

  1. Confirm the affected product and reachable code path exist in your environment.
  2. Apply the vendor-supported patch or mitigation from the primary advisory.
  3. Rescan the exact deployed revision and retain verification evidence.
Review primary references

Evidence coverage

FIRST-EPSSCVE-LIST-V5NVD-MODIFIED
SSVC priority
MEDIUM
Confidence
Not available
Aliases
None reported

Scores appear only when corresponding evidence exists. Missing data is never interpreted as zero risk.

Sources and record history

  1. GitHub advisory ↗
  2. Source repository ↗

Record history

Published Aug 5, 2026 · Last refreshed Nov 3, 2026