CVE-2024-31504Public exploitNetwork attack vector

Remote server crash via unchecked MBAP length

Published Jul 8, 2024 · Updated Aug 2, 2024

Buffer overflow in FreeModbus 2018-09-12 allows remote attackers to crash the LINUXTCP server with a crafted Modbus TCP message. The affected xMBPortTCPPool path derives a receive length from the untrusted MBAP length field and reads into a fixed 263-byte buffer without first bounding the complete frame. The LINUXTCP demo must be compiled and running with TCP mode enabled; the demonstrated consequence is a segmentation fault that interrupts the service.

CVSS severity7.5
High
EPSS probability0.55%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Buffer overflow in FreeModbus 2018-09-12 allows remote attackers to crash the LINUXTCP server with a crafted Modbus TCP message. The affected xMBPortTCPPool path derives a receive length from the untrusted MBAP length field and reads into a fixed 263-byte buffer without first bounding the complete frame. The LINUXTCP demo must be compiled and running with TCP mode enabled; the demonstrated consequence is a segmentation fault that interrupts the service.

The record

CVE
CVE-2024-31504
Published
Jul 8, 2024
Updated
Aug 2, 2024
Vendor
SILA Embedded Solutions GmbH
Product
FreeModbus
Classifications
CWE-121, CWE-120, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 8, 2024CVE publishedPublication date reported by the CVE source.
  2. Aug 2, 2024Record 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=2018-09-12

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SILA Embedded Solutions GmbH · FreeModbusversion=2018-09-12

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-121Stack-based Buffer Overflow
CWE-120Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
T1499.004Application or System Exploitation

Public exploit references

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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