CVE-2026-71254Network attack vector

Unauthenticated memory corruption via cumulative response overflow

Published Aug 5, 2026 · Updated Aug 5, 2026

Out-of-bounds write in nanoMODBUS 1.23.0 and earlier allows remote attackers to corrupt server memory via a crafted Read File Record request. handle_read_file_record() adds every subrequest's response length to an 8-bit accumulator without bounding the cumulative response, then get_n() advances through a 260-byte buffer and swap_regs() writes unconditionally. An unauthenticated Modbus TCP client can trigger a server-process crash or memory corruption; code execution depends on the target's memory protections.

CVSS severityUnavailable
Unscored
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds write in nanoMODBUS 1.23.0 and earlier allows remote attackers to corrupt server memory via a crafted Read File Record request. handle_read_file_record() adds every subrequest's response length to an 8-bit accumulator without bounding the cumulative response, then get_n() advances through a 260-byte buffer and swap_regs() writes unconditionally. An unauthenticated Modbus TCP client can trigger a server-process crash or memory corruption; code execution depends on the target's memory protections.

The record

CVE
CVE-2026-71254
Published
Aug 5, 2026
Updated
Aug 5, 2026
Vendor
Valerio De Benedetto
Product
nanoMODBUS
Classifications
T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 5, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 5, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=1.23.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Valerio De Benedetto · nanoMODBUSversion=0 <=1.23.0

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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