CVE intelligence and bounded remediation

CVE-2020-5531 — Mitsubishielectric Mi5122-Vw Firmware security vulnerability

Critical CVSS 9.8

Mitsubishi Electric MELSEC C Controller Module and MELIPC Series MI5000 MELSEC-Q Series C Controller Module(Q24DHCCPU-V, Q24DHCCPU-VG User Ethernet port (CH1, CH2): First 5 digits of serial number 21121 or before), MELSEC iQ-R Series C Controller Module / C Intelligent Function Module(R12CCPU-V Ethernet port (CH1, CH2): First 2 digits of serial number 11 or before, and RD55UP06-V Ethernet port: First 2 digits of serial number 08 or before), and MELIPC Series MI5000(MI5122-VW Ethernet port (CH1): First 2 digits of serial number 03 or before, or the firmware version 03 or before) allow remote attackers to cause a denial of service and/or malware being executed via unspecified vectors.

Severity
Critical
CVSS
9.8 (3.1)
Published
2020-02-17
CISA KEV
Not currently listed
Ecosystem
operating-system

Affected products

  • mitsubishielectric / mi5122-vw_firmware
  • mitsubishielectric / q24dhccpu-v_firmware
  • mitsubishielectric / q24dhccpu-vg_firmware
  • mitsubishielectric / r12ccpu-v_firmware
  • mitsubishielectric / rd55up06-v_firmware

Matched remediation archetype

Resource exhaustion and denial of service

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

Check exposure

  • Identify attacker-influenced work factors including input size, nesting, compression, fan-out, regex cost, allocation, recursion, retries, and connection lifetime.
  • Map per-request and shared CPU, memory, disk, descriptor, thread, queue, and downstream-service limits.
  • Determine whether authentication, tenancy, quotas, and rate controls apply before expensive processing begins.

Remediate safely

  • Bound input size, nesting, expansion, work, concurrency, queue depth, retries, and execution time before resource-intensive processing.
  • Release resources on every success, error, cancellation, and timeout path and use backpressure instead of unbounded buffering.
  • Update affected components and add small deterministic tests that assert resource ceilings rather than exhausting a host.

Authoritative sources

Complete CVE record and remediation plan

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