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CVE Record

CVE-2018-7855: A CWE-248 Uncaught Exception vulnerability exists in all versions of the Modicon M580, Modicon M340, Modico...

A CWE-248 Uncaught Exception vulnerability exists in all versions of the Modicon M580, Modicon M340, Modicon Quantum, and Modicon Premium which could cause a Denial of Service when sending invalid breakpoint parameters to the controller over Modbus

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

This vulnerability can make Schneider Electric Modicon PLC controllers stop responding when malformed breakpoint-related Modbus data is sent. For executives, the main risk is operational disruption in environments using affected controllers, especially where Modbus access is reachable beyond tightly controlled engineering networks.

Executive priority

Prioritize if these controllers support safety, production, or critical process availability. The issue is denial of service rather than data theft, but PLC disruption can still create material operational impact. Address network exposure first while confirming vendor remediation guidance.

Technical view

CVE-2018-7855 is described as a CWE-248 uncaught exception in all versions of Modicon M580, M340, Quantum, and Premium controllers. The reported impact is denial of service caused by invalid breakpoint parameters sent to the controller over Modbus.

Likely exposure

Exposure is most likely in industrial control environments running the listed Modicon controller families with Modbus access available from engineering workstations, plant networks, remote access paths, or poorly segmented environments. The bundle does not identify specific firmware branches, CPEs, or internet-exposed deployments.

Exploitation context

The source bundle does not show CISA KEV inclusion or active exploitation evidence. It does cite Schneider Electric guidance and Cisco Talos reports. Treat this as a credible ICS denial-of-service issue, not as confirmed in-the-wild exploitation.

Researcher notes

The evidence provided is limited: no CVSS vector, no CPEs, and no detailed fix text are included in the bundle. Analysis is therefore anchored to the stated affected Modicon families, Modbus attack surface, DoS impact, Schneider advisory, and Talos vulnerability reports.

Mitigation direction

  • Review Schneider Electric advisory SEVD-2019-134-11 for product-specific guidance.
  • Restrict Modbus access to trusted engineering hosts and control-system segments.
  • Remove direct internet or enterprise-network reachability to affected controllers.
  • Monitor controllers and network logs for unexpected Modbus activity or availability loss.
  • Coordinate remediation windows with operations before changing PLC firmware or network controls.

Validation and detection

  • Inventory Modicon M580, M340, Quantum, and Premium controllers in production environments.
  • Confirm whether Modbus access is limited to approved engineering systems.
  • Check deployed versions and vendor status against Schneider guidance.
  • Review firewall, VPN, and remote-access paths that can reach PLC Modbus services.
  • Validate controls in a lab or maintenance window, not against live production controllers.
Prepared
Confidence
medium
Sources
5

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

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CVE-2018-7855 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
0Timeline events
0ADP providers
4Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/aModicon M580 Modicon M340 Modicon Quantum Modicon PremiumModicon M580 Modicon M340 Modicon Quantum Modicon PremiumListed
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.