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Fencer Vulns
high 7.5

CVE-2020-7543 json

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

published 2020-12-11 5 y ago modified 2026-06-17 4 mo ago also EUVD-2020-28668

cvss
7.5
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
1.3%
EPSS 1.3% chance of exploitation in 30 days, percentile 71%
public exploits
0
none known

Summary

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in Modicon M580, Modicon M340, Legacy Controllers Modicon Quantum & Modicon Premium (see security notifications for affected versions), that could cause denial of service when a specially crafted Read Physical Memory request over Modbus is sent to the controller.

Patch / fix

  • schneider-electric modicon_m580_bmep584040_firmware 3.20
  • schneider-electric modicon_m580_bmep582040_firmware 3.20
  • schneider-electric modicon_m580_bmep586040_firmware 3.20
  • schneider-electric modicon_m580_bmep585040_firmware 3.20
  • schneider-electric modicon_m580_bmep582020_firmware 3.20
  • schneider-electric modicon_m580_bmep581020_firmware 3.20
  • schneider-electric modicon_m580_bmep584020_firmware 3.20
  • schneider-electric modicon_m580_bmep583040_firmware 3.20
  • schneider-electric modicon_m580_bmep583020_firmware 3.20
  • schneider-electric modicon_m340_bmxp341000_firmware 3.30
  • schneider-electric modicon_m340_bmxp342000_firmware 3.30
  • schneider-electric modicon_m340_bmxp3420102_firmware 3.30
  • schneider-electric modicon_m340_bmxp3420102cl_firmware 3.30
  • schneider-electric modicon_m340_bmxp342020_firmware 3.30
  • schneider-electric modicon_m340_bmxp3420302_firmware 3.30
  • schneider-electric modicon_m340_bmxp3420302cl_firmware 3.30

Exploit prediction

1.34% chance of exploitation in the next 30 days, higher than 71% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
NVD 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

  • n/a Modicon M580, Modicon M340, Legacy Controllers Modicon Quantum & Modicon Premium (see security notifications for affected versions)

Classification

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

References

Sources

Fencer Vulns 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.