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Full vulnerability report · 2020
CVE-2020-7549High confidence

n/a Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions) — Improper Check for Unusual or Exceptional Conditions

n/a · Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions)

5.3MediumCVSS 3.1
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
SEVD-2020-343-06 · CSAF 2.0 · revision 2 · finalSchneider Electric CPCERTWeb Server on Modicon M340, Legacy Offers Modicon Quantum Modicon Premium and associated Communication Modules
9 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • Schneider Electric Modicon M340 CPUs versions prior to 3.30
  • Schneider Electric Modicon M340 Ethernet Communication Modules versions prior to 3.4
  • Schneider Electric Modicon M340 Ethernet Communication Modules BMXNOE0110 versions prior to 6.6
  • Schneider Electric Modicon M340 Ethernet Communication Modules BMXNOC0401 (H) versions prior to 2.11
  • Schneider Electric Modicon Quantum Communication Modules 140NOE771x1 versions prior to 7.3
  • Schneider Electric Modicon Quantum Communication Modules All versions
  • Schneider Electric Modicon Quantum Processors with Integrated Ethernet COPRO 140CPU65xx0 All versions
  • Schneider Electric Modicon Premium Communication Modules All versions
  • Schneider Electric Modicon Premium Processors with Integrated Ethernet COPRO All versions
Summary
A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists that could cause denial of HTTP and FTP services when a series of specially crafted requests is sent to the controller over HTTP.
Remediation
Firmware V3.30 is available for all the product references. Follow this link and find the right firmware file based on model used: https://www.se.com/ww/en/product-range/1468-modiconm340/?parent-subcategory-id=3950 If customers choose not to apply the remediation, see Mitigation section.
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-28674

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in the Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions), that could cause denial of HTTP and FTP services when a series of specially crafted requests is sent to the controller over HTTP.

What

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in the Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions), that could cause denial of HTTP and FTP services when a series of specially crafted requests is sent to the controller over HTTP.

Why

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

A CWE-754: Improper Check for Unusual or Exceptional Conditions vulnerability exists in the Web Server on Modicon M340, Legacy Offers Modicon Quantum and Modicon Premium and associated Communication Modules (see security notification for affected versions), that could cause denial of HTTP and FTP services when a series of specially crafted requests is sent to the controller over HTTP.

Why

The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Improper Check for Unusual or Exceptional Conditions → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-754 ↗

CWE-754: Improper Check for Unusual or Exceptional Conditions. The product does not check or incorrectly checks for unusual or exceptional conditions that are not expected to occur frequently during day to day operation of the product.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.ALowAvailability impact: A successful attack can cause a limited loss.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-754
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

CERT-FR · French · CERTFR-2022-AVI-815Multiples vulnérabilités dans les produits Schneider

VERecord?id=CVE-2018-7857 Référence CVE CVE-2019-6807 https://www.cve.org/CVERecord?id=CVE-2019-6807 Référence CVE CVE-2020-28895 https://www.cve.org/CVERecord?id=CVE-2020-28895 Référence CVE CVE-2020-35198 https://www.cve.org/CVERecord?id=CVE-2020-35198 Référence CVE CVE-2020-35683 https://www.cve.org/CVERecord?id=CVE-2020-35683 Référence CVE CVE-2020-35684 https://www.cve.org/CVERecord?id=CVE-2020-35684 Référence CVE CVE-2020-35685 https://www.cve.org/CVERecord?id=CVE-2020-35685 Référence CVE CVE-2020-7535 https://www.cve.org/CVERecord?id=CVE-2020-7535 Référence CVE CVE-2020-7536 https://www.cve.org/CVERecord?id=CVE-2020-7536 Référence CVE CVE-2020-7549 https://www.cve.org/CVERecord?id=CVE-2020-7549 Référence CVE CVE-2020-7562 https://www.cve.org/CVERecord?id=CVE-2020-7562 Référence CVE CVE-2020-7563 https://www.cve.org/CVERecord?id=CVE-2020-7563 Référence CVE CVE-2020-7564 https://www.cve.org/CVERecord?id=CVE-2020-7564 Référence CVE CVE-2021-22785 https://www.cve.org/CVERecord?id=CVE-2021-22785 Référence CVE CVE-2021-22787 https://www.cve.org/CVERecord?id=CVE-2021-22787 Référence CVE CVE-2021-22788 https://www.cve.org/CVERecord?id=CVE-2021-22788 Référence CVE CVE-2021-31400 https://www.cve.org/CVERecord?id=CVE-2021-31400 Référence CVE CVE-2021-31401 https://www.cve.org/CVERecord?id=CVE-202

Official advisory
CERT-FR · French · CERTFR-2020-AVI-801Multiples vulnérabilités dans les produits Schneider

De multiples vulnérabilités ont été découvertes dans les produits Schneider. Elles permettent à un attaquant de provoquer une exécution de code arbitraire, un déni de service à distance et une atteinte à la confidentialité des données.

Official advisory
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Schneider Electric Modicon M340 CPUs versions prior to 3.30; Schneider Electric Modicon M340 Ethernet Communication Modules versions prior to 3.4; Schneider Electric Modicon M340 Ethernet Communication Modules BMXNOE0110 versions prior to 6.6; Schneider Electric Modicon M340 Ethernet Communication Modules BMXNOC0401 (H) versions prior to 2.11; Schneider Electric Modicon Quantum Communication Modules 140NOE771x1 versions prior to 7.3; Schneider Electric Modicon Quantum Communication Modules All versions; Schneider Electric Modicon Quantum Processors with Integrated Ethernet COPRO 140CPU65xx0 All versions; Schneider Electric Modicon Premium Communication Modules All versions; Schneider Electric Modicon Premium Processors with Integrated Ethernet COPRO All versions
Fixed
Schneider Electric Modicon M340 CPUs 3.30; Schneider Electric Modicon M340 Ethernet Communication Modules 3.4; Schneider Electric Modicon M340 Ethernet Communication Modules BMXNOE0110 6.6; Schneider Electric Modicon M340 Ethernet Communication Modules BMXNOC0401 (H) 2.11; Schneider Electric Modicon Quantum Communication Modules 140NOE771x1 7.3
Action
Firmware V3.30 is available for all the product references. Follow this link and find the right firmware file based on model used: https://www.se.com/ww/en/product-range/1468-modiconm340/?parent-subcategory-id=3950 If customers choose not to apply the remediation, see Mitigation section.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 11 Dec 2020 · Last source change 28 May 2026, 21:05 UTC · CWE-754 · Improper Check for Unusual or Exceptional Conditions

CVE recordCVE.org · 5.2
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2020-28674
Product sourceVendor CSAF · Schneider Electric CPCERT
Remediation sourceVendor CSAF · Schneider Electric CPCERT
CWE sourceCNA
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates →

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2020-28674↗Vendor CSAF · Schneider Electric CPCERT↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2020-7549 · cve.blacktree.nl