CVE-2019-6821
mediumpriority · track · 27OT risk · elevatedEPSS 0.019 · 80 %ileEURUUSEPSS · scored 2026-10-27
CWE-330: Use of Insufficiently Random Values vulnerability, which could cause the hijacking of the TCP connection when using Ethernet communication in Modicon M580 firmware versions prior to V2.30, and all firmware versions of Modicon M340, Modicon Premium, Modicon Quantum.
remediations
Vendor fix, mitigation, or workaround guidance, as published by each source.
A vendor fix is available.
- FixedModicon M340cisa_csaf_ot
Configure the Access Control List following the recommendations of the user manual “Modicon M340 for Ethernet Communications Modules and Processors User Manual,” in the chapter titled “Messaging Configuration Parameters,” which is available here: https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000
https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000 - FixedModicon M580cisa_csaf_ot
Configure the Access Control List following the recommendations of the user manual “Modicon M340 for Ethernet Communications Modules and Processors User Manual,” in the chapter titled “Messaging Configuration Parameters,” which is available here: https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000
https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000 - FixedModicon Premiumcisa_csaf_ot
Configure the Access Control List following the recommendations of the user manual “Modicon M340 for Ethernet Communications Modules and Processors User Manual,” in the chapter titled “Messaging Configuration Parameters,” which is available here: https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000
https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000 - FixedModicon Quantumcisa_csaf_ot
Configure the Access Control List following the recommendations of the user manual “Modicon M340 for Ethernet Communications Modules and Processors User Manual,” in the chapter titled “Messaging Configuration Parameters,” which is available here: https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000
https://download.schneiderelectric.com/files?p_enDocType=User+guide&p_File_Name=31007131_K01_000_16.pdf&p_Doc_Ref=31007131K01000 - MitigationModicon M340cisa_csaf_ot
Modicon Premium and Modicon Quantum: Set up network segmentation and implement a firewall to block all unauthorized access to all TCP ports.
- MitigationModicon M580cisa_csaf_ot
Modicon Premium and Modicon Quantum: Set up network segmentation and implement a firewall to block all unauthorized access to all TCP ports.
- MitigationModicon Premiumcisa_csaf_ot
Modicon Premium and Modicon Quantum: Set up network segmentation and implement a firewall to block all unauthorized access to all TCP ports.
- MitigationModicon Quantumcisa_csaf_ot
Modicon Premium and Modicon Quantum: Set up network segmentation and implement a firewall to block all unauthorized access to all TCP ports.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.4–7.5
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (17)
Products and version ranges known to be affected.
- n/a Modicon Controllers, Modicon M580 firmware versions prior to V2.30, and all firmware versions of Modicon M340, Modicon Premium, Modicon Quantum≤ Modicon Controllers, Modicon M580 firmware versions prior to V2.30, and all firmware versions of Modicon M340, Modicon Premium, Modicon Quantumenisa_euvdEU
- schneider-electric modicon m340 firmwareall versionsnvdUScpe:2.3:o:schneider-electric:modicon_m340_firmware:*:*:*:*:*:*:*:*
- schneider-electric modicon m580 firmware< 2.30nvdUScpe:2.3:o:schneider-electric:modicon_m580_firmware:*:*:*:*:*:*:*:*
- schneider-electric modicon premium firmwareall versionsnvdUScpe:2.3:o:schneider-electric:modicon_premium_firmware:*:*:*:*:*:*:*:*
- schneider-electric modicon quantum firmwareall versionsnvdUScpe:2.3:o:schneider-electric:modicon_quantum_firmware:*:*:*:*:*:*:*:*
advisories (1)
Vendor and ecosystem advisories describing this.
- ICSA-19-136-01Schneider Electric Modicon Controllers2019-05-16icsa · cisa_csaf_otUS
Successful exploitation of this vulnerability could allow an attacker to hijack TCP connections or cause information leakage.
also known as (4)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (13)
External citations — patches, advisories, analysis.
- http://www.schneider-electric.com/site/home/index.cfm/ww/?selectCountry=truecnnvd
- http://www.securityfocus.com/bid/108366cnnvd
- https://download.schneider-electric.com/files?p_enDocType=Technical+leaflet&p_File_Name=SEVD-2019-134-03+-+Modicon+Controller.pdf&p_Doc_Ref=SEVD-2019-134-03cnnvd
- https://ics-cert.us-cert.gov/advisories/ICSA-19-136-01cnnvd
- https://nvd.nist.gov/vuln/detail/CVE-2019-6821cnnvd
- https://www.schneider-electric.com/en/download/document/SEVD-2019-134-03/cnnvd
- https://www.securityfocus.com/bid/108366cnnvd
- http://www.securityfocus.com/bid/108366enisa_euvd
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