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Fencer Intel
high 7.5

CVE-2019-6856 json

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in Modicon M580, Modicon M340, Modicon Quantum, Modico…

published 6y ago modified 4mo ago also EUVD-2019-16410

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
1.6%
EPSS 1.6% chance of exploitation in 30 days, percentile 76%
public exploits
0
none known

Summary

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in Modicon M580, Modicon M340, Modicon Quantum, Modicon Premium (see security notification for specific versions) which could cause a Denial of Service when writing specific physical memory blocks using Modbus TCP.

Patch / fix

  • schneider-electric modicon_m580_firmware 2.80
  • schneider-electric modicon_m340_firmware 3.01
  • schneider-electric tsxh5744m_firmware 3.20
  • schneider-electric tsxh5724m_firmware 3.20
  • schneider-electric tsxp576634m_firmware 3.20
  • schneider-electric tsxp57554m_firmware 3.20
  • schneider-electric tsxp575634m_firmware 3.20
  • schneider-electric tsxp57454m_firmware 3.20
  • schneider-electric tsxp574634m_firmware 3.20
  • schneider-electric tsxp57354m_firmware 3.20
  • schneider-electric tsxp573634m_firmware 3.20
  • schneider-electric tsxp57304m_firmware 3.20
  • schneider-electric tsxp57254m_firmware 3.20
  • schneider-electric tsxp572634m_firmware 3.20
  • schneider-electric tsxp57204m_firmware 3.20
  • schneider-electric tsxp571634m_firmware 3.20
  • schneider-electric tsxp57154m_firmware 3.20
  • schneider-electric tsxp57104m_firmware 3.20
  • schneider-electric 140cpu65150_firmware 3.52
  • schneider-electric 140cpu65160_firmware 3.52

Is CVE-2019-6856 in your stack? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

cisa ICSA-20-016-01 updated cvss 7.5

Schneider Electric Modicon Controllers (Update A)

  • Schneider Electric Software, LLC Modicon M340 < 3.01 Schneider Electric Software, LLC Modicon M580 < 2.80 Schneider Electric Software, LLC Modicon Premium < 3.20 Schneider Electric Software, LLC Modicon Quantum < 3.60, < 3.52
    affected: vendor fix, mitigation “BMEP584040: Specific Modicon M580 firmware v3.10” schneider-electric.com

From CISA ICS and IT advisories (CSAF, https://github.com/cisagov/CSAF), a U.S. Government work; changed: reduced to products, statuses and remediations. CISA notification · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
5mo ago

Exploit prediction

1.63% chance of exploitation in the next 30 days, higher than 76% of all scored CVEs (FIRST EPSS, 2026-11-09).

CVSS scores

assigned by version score vector
CISA ADP 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD 2.0 5.0 AV:N/AC:L/Au:N/C:N/I:N/A:P

Affected products

  • Schneider Electric SE Modicon M580, Modicon M340, Modicon Quantum, Modicon Premium (see security notification for specific versions)

Classification

Weakness
  • CWE-754 Improper Check for Unusual or Exceptional Conditions

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.