CVE-2018-7843

HIGH

Modicon M580, M340, Quantum, and Premium Firmware - Denial of Service via Invalid Modbus Memory Block Read

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2018-7843. PoCs published by yanissec.

AI-analyzed exploit summary This PoC exploits a DoS vulnerability in Schneider Electric Modicon PLCs by sending malformed Modbus packets to trigger a memory read operation, causing the device to crash. The script iterates through memory blocks until the connection is terminated.

Description

A CWE-248: Uncaught Exception vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause denial of service when reading memory blocks with an invalid data size or with an invalid data offset in the controller over Modbus.

Exploits (1)

nomisec WORKING POC
by yanissec · poc
https://github.com/yanissec/CVE-2018-7843

This PoC exploits a DoS vulnerability in Schneider Electric Modicon PLCs by sending malformed Modbus packets to trigger a memory read operation, causing the device to crash. The script iterates through memory blocks until the connection is terminated.

Classification
Working Poc 90%
Attack Type
Dos
Complexity
Trivial
Reliability
Reliable
Target: Schneider Electric Modicon M580, M340, Premium, Quantum (versions < 2.80, 3.10, 3.20, 3.60 respectively)
No auth needed
Prerequisites: Network access to the target PLC · Modbus/TCP port (502) accessible
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (2)

Core 2
Core References
Exploit, Third Party Advisory x_refsource_misc
https://www.talosintelligence.com/vulnerability_reports/TALOS-2018-0738

Scores

CVSS v3 7.5
EPSS 0.0329
EPSS Percentile 86.9%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Details

CWE
CWE-125
Status published
Products (4)
schneider-electric/modicon_m340_firmware
schneider-electric/modicon_m580_firmware
schneider-electric/modicon_premium_firmware
schneider-electric/modicon_quantum_firmware
Published May 22, 2019
Tracked Since Feb 18, 2026