How severe is CVE-2019-6821?

CVE-2019-6821 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2019-6821 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-6821?

CVE-2019-6821 primarily affects Schneider-electric Modicon M580 Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-6821?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2019-6821 published?

CVE-2019-6821 was published on 2019-05-22 and last updated on 2026-06-17.

CVE-2019-6821

CVE-2019-6821 is a medium-severity vulnerability in Schneider-electric Modicon M580 Firmware with a CVSS 3.x base score of 6.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-330.

Key facts

Severity: Medium (CVSS 3.x base score 6.5)
CVSS v2: 6.4
EPSS exploit prediction: 2% (78th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-330
Affected product: Schneider-electric Modicon M580 Firmware
Published: 2019-05-22
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2019-6821?: 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.
How severe is CVE-2019-6821?: CVE-2019-6821 has a CVSS 3.x base score of 6.5, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2019-6821 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (78th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-6821?: CVE-2019-6821 primarily affects Schneider-electric Modicon M580 Firmware. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-6821?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2019-6821 published?: CVE-2019-6821 was published on 2019-05-22 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:schneider-electric:modicon_m580_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:schneider-electric:modicon_m340_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:schneider-electric:modicon_quantum_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:schneider-electric:modicon_premium_firmware:*:*:*:*:*:*:*:*

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