CVE intelligence and bounded remediation

CVE-2020-5656 — Mitsubishielectric Melsec Iq-Rj71Eip91 Firmware security vulnerability

Critical CVSS 9.8

Improper access control vulnerability in TCP/IP function included in the firmware of MELSEC iQ-R series (RJ71EIP91 EtherNet/IP Network Interface Module First 2 digits of serial number are '02' or before, RJ71PN92 PROFINET IO Controller Module First 2 digits of serial number are '01' or before, RD81DL96 High Speed Data Logger Module First 2 digits of serial number are '08' or before, RD81MES96N MES Interface Module First 2 digits of serial number are '04' or before, and RD81OPC96 OPC UA Server Module First 2 digits of serial number are '04' or before) allows a remote unauthenticated attacker to stop the network functions of the products or execute a malicious program via a specially crafted packet.

Severity
Critical
CVSS
9.8 (3.1)
Published
2020-11-02
CISA KEV
Not currently listed
Ecosystem
operating-system

Affected products

  • mitsubishielectric / melsec_iq-rj71eip91_firmware
  • mitsubishielectric / melsec_iq-rj71pn92_firmware
  • mitsubishielectric / melsec_iq-rd81dl96_firmware
  • mitsubishielectric / melsec_iq-rd81mes96n_firmware
  • mitsubishielectric / melsec_iq-rd81opc96_firmware

Matched remediation archetype

General vulnerability remediation

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Confirm the affected component, deployment paths, reachable interfaces, and enabled features from inventories and configuration, without probing production destructively.
  • Compare the advisory's affected conditions with the repository lockfiles, build manifests, artifacts, and runtime inventory.
  • Identify data sensitivity, trust boundaries, and privilege level for every confirmed affected deployment.

Remediate safely

  • Apply a vendor-supported fix or remove the affected component or feature; record the selected change and its source in the repository.
  • Update direct and transitive dependency locks, generated artifacts, deployment manifests, and asset inventories together.
  • Add a regression test for the documented unsafe condition using inert inputs and preserve rollback instructions.

Authoritative sources

Complete CVE record and remediation plan

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