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Fx5uc FirmwareOperating system · Mitsubishielectric

CVE-2022-25155

HIGH · 8.1 CVSS v3.1 Published 2022-04-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
90/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Use of Password Hash Instead of Password for Authentication vulnerability in Mitsubishi Electric MELSEC iQ-F series FX5U(C) CPU all versions, Mitsubishi Electric MELSEC iQ-F series FX5UJ CPU all versions, Mitsubishi Electric MELSEC iQ-R series R00/01/02CPU all versions, Mitsubishi Electric MELSEC iQ-R series R04/08/16/32/120(EN)CPU all versions, Mitsubishi Electric MELSEC iQ-R series R08/16/32/120SFCPU all versions, Mitsubishi Electric MELSEC iQ-R series R08/16/32/120PCPU all versions, Mitsubishi Electric MELSEC iQ-R series R08/16/32/120PSFCPU all versions, Mitsubishi Electric MELSEC iQ-R series RJ71GN11-T2 all versions, Mitsubishi Electric MELSEC iQ-R series RJ71GN11-EIP all versions, Mitsubishi Electric MELSEC iQ-R series RJ71C24(-R2/R4) all versions, Mitsubishi Electric MELSEC iQ-R series RJ71EN71 all versions, Mitsubishi Electric MELSEC iQ-R series RJ72GF15-T2 all versions, Mitsubishi Electric MELSEC Q series Q03UDECPU all versions, Mitsubishi Electric MELSEC Q series Q04/06/10/13/20/26/50/100UDEHCPU all versions, Mitsubishi Electric MELSEC Q series Q03/04/06/13/26UDVCPU all versions, Mitsubishi Electric MELSEC Q series Q04/06/13/26UDPVCPU all versions, Mitsubishi Electric MELSEC Q series QJ71C24N(-R2/R4) all versions, Mitsubishi Electric MELSEC Q series QJ71E71-100 all versions, Mitsubishi Electric MELSEC Q series QJ72BR15 all versions, Mitsubishi Electric MELSEC Q series QJ72LP25(-25/G/GE) all versions, Mitsubishi Electric MELSEC L series L02/06/26CPU(-P) all versions, Mitsubishi Electric MELSEC L series L26CPU-(P)BT all versions, Mitsubishi Electric MELSEC L series LJ71C24(-R2) all versions, Mitsubishi Electric MELSEC L series LJ71E71-100 all versions and Mitsubishi Electric MELSEC L series LJ72GF15-T2 all versions allows a remote unauthenticated attacker to login to the product by replaying an eavesdropped password hash.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

The vulnerability is a password hash replay issue where the authentication mechanism accepts a password hash instead of requiring the actual password. An attacker who intercepts (eavesdrops) the password hash during authentication can replay it to gain unauthorized access to the PLC device without knowing the original password.

MitigationImplement challenge-response authentication with anti-replay mechanisms (e.g., nonces, timestamps, session-specific tokens) and use proper cryptographic protocols instead of simple hash comparison. Coordinate with Mitsubishi Electric for firmware updates and apply vendor-recommended security controls.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Fx5uc FirmwareOperating system
Affected:all versions
Fx5uc 32mr\/ds Ts FirmwareOperating system
Affected:all versions
Fx5uc 32mt\/d FirmwareOperating system
Affected:all versions
Fx5uc 32mt\/dss FirmwareOperating system
Affected:all versions
Fx5uj 24mr\/es FirmwareOperating system
Affected:all versions
Fx5uj 24mt\/es FirmwareOperating system
Affected:all versions
Fx5uj 24mt\/ess FirmwareOperating system
Affected:all versions
Fx5uj 40mr\/es FirmwareOperating system
Affected:all versions

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify PLC model
    Check the product label or system configuration to confirm the exact model number (e.g., FX5UC-32MR/DS, FX5UJ-24MT/ES)
    Affected if Model is FX5UC or FX5UJ series (any variant listed in the affected products)
  2. Verify firmware version
    Access the PLC programming software (GX Works3) or device web interface and check the firmware version under system information or device properties
    Affected if Firmware version is present (all versions of affected models are vulnerable)
  3. Confirm Ethernet communication is enabled
    Check PLC configuration for Ethernet port settings and ensure the built-in Ethernet or add-on module is configured and active
    Affected if Ethernet communication is enabled - the vulnerability is exploitable over the network
  4. Check authentication configuration
    Review the PLC security settings in GX Works3 under Security -> User Authentication or Password Settings to confirm password-based authentication is in use
    Affected if Password authentication is configured without additional challenge-response mechanisms
  5. Assess network exposure
    Review network topology and firewall rules to determine if the PLC Ethernet port is accessible from untrusted networks
    Affected if PLC is accessible from networks where an attacker could intercept authentication traffic

You are affected if you use any FX5UC or FX5UJ series PLC model with Ethernet communication enabled and password-based authentication configured.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Implement challenge-response authentication with anti-replay mechanisms (e.g., nonces, timestamps, session-specific tokens) and use proper cryptographic protocols instead of simple hash comparison. Coordinate with Mitsubishi Electric for firmware updates and apply vendor-recommended security controls.

Fix this in Fx5uc Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA8.0 h
44.0 hours of engineering $7,720
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2022-25155 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data