What’s Vulnerable › Vulnerabilities

CVE-2019-6821

• Severity: medium (CVSS 6.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.9% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-05-22 · updated 2026-06-17
• Weakness: CWE-330

Description

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.

Affected products

• Schneider-Electric Modicon M340 Firmware: all versions
• Schneider Electric SE Modicon M580: before 2.30 — fixed in 2.30
• Schneider-Electric Modicon Premium Firmware: all versions
• Modicon Quantum - all firmware versions: all versions

How to fix

Upgrade to a fixed version: Schneider Electric SE Modicon M580 2.30. Check the vendor advisory for mitigations.

References

• http://www.securityfocus.com/bid/108366
• https://ics-cert.us-cert.gov/advisories/ICSA-19-136-01
• https://www.schneider-electric.com/en/download/document/SEVD-2019-134-03/
• http://www.securityfocus.com/bid/108366
• https://ics-cert.us-cert.gov/advisories/ICSA-19-136-01
• https://www.schneider-electric.com/en/download/document/SEVD-2019-134-03/

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