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CVE Record

CVE-2018-7758: A denial of service vulnerability exists in Schneider Electric's MiCOM Px4x (P540 range excluded) with lega...

A denial of service vulnerability exists in Schneider Electric's MiCOM Px4x (P540 range excluded) with legacy Ethernet board, MiCOM P540D Range with Legacy Ethernet Board, and MiCOM Px4x Rejuvenated could lose network communication in case of TCP/IP open requests on port 20000 (DNP3oE) if an older TCI/IP session is still open with identical IP address and port number.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysisunknown

Security readout for executives and security teams

Plain-English summary

This vulnerability can make affected Schneider Electric MiCOM protection devices lose network communication. In an electrical protection environment, that is mainly an availability and operations risk, not a data theft issue. The public bundle does not provide a CVSS score or confirm active exploitation.

Executive priority

Prioritize assessment where affected MiCOM devices support critical electrical protection or remote operations. Business urgency depends on network exposure and operational dependency, because the documented impact is loss of communication rather than confirmed compromise.

Technical view

CVE-2018-7758 affects Schneider Electric MiCOM Px4x devices with legacy Ethernet boards, excluding the P540 range, plus MiCOM P540D legacy Ethernet board and MiCOM Px4x Rejuvenated. Network communication may be lost when TCP/IP open requests hit port 20000 for DNP3 over Ethernet while an older identical session remains open.

Likely exposure

Exposure is likely limited to organizations operating the named MiCOM relay products with legacy Ethernet hardware and reachable DNP3 over Ethernet service on port 20000. Internet exposure would materially increase concern, but the bundle does not state exposed deployments.

Exploitation context

The bundle describes a denial-of-service condition triggered through TCP/IP session handling. It does not cite CISA KEV listing, public exploitation, exploit code, or real-world incidents. Treat exploitation status as unconfirmed.

Researcher notes

Evidence is limited to the CVE description and Schneider advisory links. No CVSS, CWE, patch text, or exploit status is included in the bundle. Avoid assuming all MiCOM Px4x products are affected; the P540 range exclusion and P540D inclusion matter.

Mitigation direction

  • Identify affected MiCOM models and legacy Ethernet boards in OT inventories.
  • Check Schneider Electric advisories for supported remediation or configuration guidance.
  • Restrict access to DNP3 over Ethernet port 20000 to trusted management networks.
  • Ensure relay networks are segmented from corporate and internet-facing networks.
  • Monitor affected devices for unexpected network communication loss.

Validation and detection

  • Confirm whether deployed MiCOM devices match the affected product list.
  • Verify whether port 20000 is reachable from untrusted network segments.
  • Review firewall rules and OT access paths to affected relay networks.
  • Check operational logs for unexplained MiCOM communication loss events.
  • Compare device firmware and hardware details against Schneider advisory guidance.
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-2018-7758 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
Schneider Electric SEMiCOM P540D Range with Legacy Ethernet BoardMiCOM P540D Range with Legacy Ethernet Board, MiCOM Px4x with Legacy Ethernet Board, MiCOM Px4x RejuvenatedListed
Weakness

CWE details

No CWE listed

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