CVE intelligence and bounded remediation

CVE-2020-5653 — Mitsubishielectric Melsec Iq-Rj71Eip91 Firmware security vulnerability

Critical CVSS 9.8

Buffer overflow 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
Weaknesses
CWE-120

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

Buffer bounds, memory safety, and memory corruption

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

Check exposure

  • Identify affected native-code versions, build flags, architectures, parsers, codecs, drivers, and input paths in all shipped artifacts.
  • Determine whether untrusted data reaches the affected routine and the process privilege, sandbox, and network exposure.
  • Confirm statically linked, vendored, firmware, and platform-provided copies, not only package-manager records.

Remediate safely

  • Apply the maintained upstream correction or replace the affected component, then rebuild every dependent artifact from clean inputs.
  • Adopt bounds-checked interfaces, validated sizes and integer conversions, clear ownership, and memory-safe components where practical.
  • Enable supported compiler and runtime hardening and add sanitized tests and fuzz regression seeds derived from non-weaponized fixtures.

Authoritative sources

Complete CVE record and remediation plan

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