How severe is CVE-2018-7833?

CVE-2018-7833 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-7833 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-7833?

CVE-2018-7833 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-2018-7833?

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

When was CVE-2018-7833 published?

CVE-2018-7833 was published on 2018-12-17 and last updated on 2026-06-17.

CVE-2018-7833

CVE-2018-7833 is a high-severity vulnerability in Schneider-electric Modicom M340 Firmware with a CVSS 3.x base score of 7.5. 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-754.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-754
Affected product: Schneider-electric Modicom M340 Firmware
Published: 2018-12-17
Last modified: 2026-06-17

Description

An Improper Check for Unusual or Exceptional Conditions vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum PLCs and BMXNOR0200 where an unauthenticated user can send a specially crafted XML data via a POST request to cause the web server to become unavailable

Frequently asked questions

What is CVE-2018-7833?: An Improper Check for Unusual or Exceptional Conditions vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum PLCs and BMXNOR0200 where an unauthenticated user can send a specially crafted XML data via a POST request to cause the web server to become unavailable
How severe is CVE-2018-7833?: CVE-2018-7833 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-7833 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-7833?: CVE-2018-7833 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-2018-7833?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2018-7833 published?: CVE-2018-7833 was published on 2018-12-17 and last updated on 2026-06-17.

References

https://www.schneider-electric.com/en/download/document/SEVD-2018-327-01/

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-2018-7811 — Critical (CVSS 9.8): An Unverified Password Change vulnerability exists in the embedded web servers in all Modicon M340, Premium, Quantum…
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-2018-7812 — 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,…

All CVEs affecting Schneider-electric Modicom M340 Firmware →

Other CWE-754 (Improper Check for Unusual or Exceptional Conditions) vulnerabilities

CVE-2026-24054 — Critical (CVSS 10.0): Kata Containers is an open source project focusing on a standard implementation of lightweight Virtual Machines (VMs)…
CVE-2021-0211 — Critical (CVSS 10.0): An improper check for unusual or exceptional conditions in Juniper Networks Junos OS and Junos OS Evolved Routing…
CVE-2026-8091 — Critical (CVSS 9.8): Incorrect boundary conditions in the Audio/Video: Playback component. This vulnerability was fixed in Firefox 150,…
CVE-2024-52316 — Critical (CVSS 9.8): Unchecked Error Condition vulnerability in Apache Tomcat. If Tomcat is configured to use a custom Jakarta…
CVE-2024-7826 — Critical (CVSS 9.8): Improper Check for Unusual or Exceptional Conditions vulnerability in Webroot SecureAnywhere - Web Shield on Windows,…
CVE-2023-37303 — Critical (CVSS 9.8): An issue was discovered in the CheckUser extension for MediaWiki through 1.39.3. In certain situations, an attempt to…

Browse all CWE-754 (Improper Check for Unusual or Exceptional Conditions) vulnerabilities →