CVE intelligence and bounded remediation

CVE-2021-20598 — Mitsubishielectric R08Sfcpu Firmware security vulnerability

Medium CVSS 5.3

Overly Restrictive Account Lockout Mechanism vulnerability in Mitsubishi Electric MELSEC iQ-R series CPU modules (R08/16/32/120SFCPU all versions, R08/16/32/120PSFCPU all versions) allows a remote unauthenticated attacker to lockout a legitimate user by continuously trying login with incorrect password.

Severity
Medium
CVSS
5.3 (3.1)
Published
2021-08-06
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-287

Affected products

  • mitsubishielectric / r08sfcpu_firmware
  • mitsubishielectric / r16sfcpu_firmware
  • mitsubishielectric / r32sfcpu_firmware
  • mitsubishielectric / r120sfcpu_firmware
  • mitsubishielectric / r08psfcpu_firmware
  • mitsubishielectric / r16psfcpu_firmware

Showing 6 representative product identities from 8 source matches. Confirm exact affected versions with the linked vendor and NVD evidence.

Matched remediation archetype

Authentication bypass and missing authentication

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Check exposure

  • Map every affected endpoint and protocol path, including alternate ports, legacy routes, recovery flows, service accounts, and machine-to-machine access.
  • Confirm which deployments enable the affected authentication mode and whether the interface is reachable from untrusted networks.
  • Review session, token, credential, and proxy trust configuration without attempting account takeover.

Remediate safely

  • Apply the supported fix and centralize fail-closed authentication before protected request handling.
  • Remove default or embedded credentials, rotate affected secrets and sessions, and bind authentication decisions to the intended audience and channel.
  • Add negative tests for alternate routes, malformed or absent credentials, recovery flows, and proxy-derived identity.

Authoritative sources

Complete CVE record and remediation plan

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