How severe is CVE-2018-7811?

CVE-2018-7811 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-7811 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (88th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-7811?

CVE-2018-7811 primarily affects Schneider-electric Modicom M340 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-2018-7811?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2018-7811 published?

CVE-2018-7811 was published on 2018-11-30 and last updated on 2026-06-17.

CVE-2018-7811

CVE-2018-7811 is a critical-severity vulnerability in Schneider-electric Modicom M340 Firmware with a CVSS 3.x base score of 9.8. 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-640.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 5.0
EPSS exploit prediction: 3% (88th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-640
Affected product: Schneider-electric Modicom M340 Firmware
Published: 2018-11-30
Last modified: 2026-06-17

Description

An Unverified Password Change vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum PLCs and BMXNOR0200 which could allow an unauthenticated remote user to access the change password function of the web server

Frequently asked questions

What is CVE-2018-7811?: An Unverified Password Change vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum PLCs and BMXNOR0200 which could allow an unauthenticated remote user to access the change password function of the web server
How severe is CVE-2018-7811?: CVE-2018-7811 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-7811 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (88th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-7811?: CVE-2018-7811 primarily affects Schneider-electric Modicom M340 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-2018-7811?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2018-7811 published?: CVE-2018-7811 was published on 2018-11-30 and last updated on 2026-06-17.

References

Affected products (4)

cpe:2.3:o:schneider-electric:modicom_m340_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:schneider-electric:modicom_premium_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:schneider-electric:modicom_quantum_firmware:*:*:*:*:*:*:*:*
cpe:2.3:o:schneider-electric:modicom_bmxnor0200h_firmware:*:*:*:*:*:*:*:*

More vulnerabilities in Schneider-electric Modicom M340 Firmware

CVE-2018-7809 — Critical (CVSS 9.8): An Unverified Password Change vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum…
CVE-2018-7831 — High (CVSS 8.8): An Improper Neutralization of Script-Related HTML Tags in a Web Page (Basic XSS) vulnerability exists in the embedded…
CVE-2018-7833 — High (CVSS 7.5): An Improper Check for Unusual or Exceptional Conditions vulnerability exists in the embedded web servers in all Modicon…
CVE-2018-7812 — High (CVSS 7.5): An Information Exposure through Discrepancy vulnerability exists in the embedded web servers in all Modicon M340,…
CVE-2018-7830 — High (CVSS 7.5): Improper Neutralization of CRLF Sequences in HTTP Headers ('HTTP Response Splitting') vulnerability exists in the…
CVE-2018-7804 — Medium (CVSS 6.1): A URL Redirection to Untrusted Site vulnerability exists in the embedded web servers in all Modicon M340, Premium,…

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