CVE-2019-6857Network attack vector

Controller denial of service via memory reads

Published Jan 6, 2020 · Updated May 29, 2026

Improper condition handling in Modicon M580, M340, Quantum, and Premium controllers allows remote attackers to interrupt controller service. The Modbus TCP memory-block read path mishandles requests for specific blocks and places the controller in a denial-of-service state. No authentication or user interaction is required; network reachability alone exposes controller availability, not data confidentiality or integrity.

CVSS severity7.5
High
EPSS probability1.63%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper condition handling in Modicon M580, M340, Quantum, and Premium controllers allows remote attackers to interrupt controller service. The Modbus TCP memory-block read path mishandles requests for specific blocks and places the controller in a denial-of-service state. No authentication or user interaction is required; network reachability alone exposes controller availability, not data confidentiality or integrity.

The record

CVE
CVE-2019-6857
Published
Jan 6, 2020
Updated
May 29, 2026
Vendor
Unknown vendor
Product
Unknown product
Classifications
CWE-754, T0814
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jan 6, 2020CVE publishedPublication date reported by the CVE source.
  2. May 29, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS: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 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 exploitUnconfirmed

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T0814Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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