CVE-2021-20587Network attack vector

Application crash via crafted device reply

Published Feb 19, 2021 · Updated Jun 12, 2025

Heap-based buffer overflow in Mitsubishi Electric FA engineering software allows remote attackers to crash applications with crafted replies. The vendor identifies the locus only as processing of spoofed MELSEC, GOT, or FREQROL reply packets and does not disclose the affected function or failed bounds check. Exploitation requires a product to accept a malicious device reply; code execution remains unconfirmed, while application denial of service is reproduced.

CVSS severity7.5
High
EPSS probability3.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in Mitsubishi Electric FA engineering software allows remote attackers to crash applications with crafted replies. The vendor identifies the locus only as processing of spoofed MELSEC, GOT, or FREQROL reply packets and does not disclose the affected function or failed bounds check. Exploitation requires a product to accept a malicious device reply; code execution remains unconfirmed, while application denial of service is reproduced.

The record

CVE
CVE-2021-20587
Published
Feb 19, 2021
Updated
Jun 12, 2025
Vendor
Mitsubishi Electric Corporation
Product
MELSOFT PX Developer
Classifications
CWE-122, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Feb 19, 2021CVE publishedPublication date reported by the CVE source.
  2. Jun 12, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=1.53F and prior

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Mitsubishi Electric Corporation · MELSOFT PX Developerversion=1.53F and prior
Mitsubishi Electric Corporation · MELSOFT CW Configuratorversion=1.011M and prior
Mitsubishi Electric Corporation · MX Componentversion=5.001B and prior
Mitsubishi Electric Corporation · Network Interface Board CC IE Control Utilityversion=1.29F and prior
Mitsubishi Electric Corporation · iQ Monozukuri ANDON (Data Transfer)version=1.003D and prior
Mitsubishi Electric Corporation · Setting/Monitoring Tools for the C Controller Moduleversion=4.12N and prior
Mitsubishi Electric Corporation · GX Works3version=1.070Y and prior
Mitsubishi Electric Corporation · GX Explorerversion=all versions
Mitsubishi Electric Corporation · M_CommDTM-HARTversion=all versions
Mitsubishi Electric Corporation · MH11 SettingTool Version2version=2.004E and prior
Mitsubishi Electric Corporation · Data Transferversion=3.44W and prior
Mitsubishi Electric Corporation · Network Interface Board MNETH Utilityversion=34L and prior
Mitsubishi Electric Corporation · GT SoftGOT1000 Version3version=3.245F and prior
Mitsubishi Electric Corporation · Network Interface Board CC-Link Ver.2 Utilityversion=1.23Z and prior
Mitsubishi Electric Corporation · M_CommDTM-IO-Linkversion=1.03D and prior
Mitsubishi Electric Corporation · FR Configuratorversion=all versions
Mitsubishi Electric Corporation · EZSocketversion=5.4 and prior
Mitsubishi Electric Corporation · FR Configurator SW3version=all versions
Mitsubishi Electric Corporation · GT Designer3 Version1 (GOT1000)version=1.250L and prior
Mitsubishi Electric Corporation · MI Configuratorversion=1.004E and prior
Mitsubishi Electric Corporation · MELSEC WinCPU Setting Utilityversion=all versions
Mitsubishi Electric Corporation · CPU Module Logging Configuration Toolversion=1.112R and prior
Mitsubishi Electric Corporation · MELSOFT EM Software Development Kitversion=1.015R and prior
Mitsubishi Electric Corporation · GT SoftGOT2000 Version1version=1.250L and prior
Mitsubishi Electric Corporation · GT Designer3 Version1 (GOT2000)version=1.250L and prior
Mitsubishi Electric Corporation · GX RemoteService-Iversion=all versions
Mitsubishi Electric Corporation · GX IEC Developerversion=all versions
Mitsubishi Electric Corporation · iQ Monozukuri Process Remote Monitoring (Data Transfer)version=1.002C and prior
Mitsubishi Electric Corporation · Network Interface Board CC IE Field Utilityversion=1.16S and prior
Mitsubishi Electric Corporation · GX Configurator-QPversion=all versions
Mitsubishi Electric Corporation · RT ToolBox2version=3.73B and prior
Mitsubishi Electric Corporation · MT Works2version=1.167Z and prior
Mitsubishi Electric Corporation · GX LogViewerversion=1.115U and prior
Mitsubishi Electric Corporation · MELSOFT Navigatorversion=2.74C and prior
Mitsubishi Electric Corporation · GX Configurator-DPversion=7.14Q and prior
Mitsubishi Electric Corporation · MELSOFT RT ToolBox3version=1.82L and prior
Mitsubishi Electric Corporation · FR Configurator2version=1.24A and prior
Mitsubishi Electric Corporation · GX Developerversion=8.506C and prior
Mitsubishi Electric Corporation · MELFA-Worksversion=4.4 and prior
Mitsubishi Electric Corporation · SLMP Data Collectorversion=1.04E and prior
Mitsubishi Electric Corporation · MELSOFT GX Works2version=1.597X and prior

Published CVSS scores

7.5Mitsubishi Electric CorporationCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
7.5Mitsubishi Electric Corporation CNACVSS: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

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

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

CWE-122Heap-based Buffer Overflow
T1499.004Endpoint Denial of Service: Application 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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