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Fx5uc FirmwareOperating system · Mitsubishielectric

CVE-2022-25157

CRITICAL · 9.1 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 →
100/100
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 R16/32/64MTCPU 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 RJ71GF11-T2 all versions, Mitsubishi Electric MELSEC iQ-R series RJ71GP21(S)-SX 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 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 disclose or tamper with the information in the product by using 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

This is a critical authentication design flaw where the system accepts password hashes as valid credentials, rather than using the hash to verify the actual password. An attacker who intercepts (eavesdrops) the password hash can replay it directly to authenticate without knowing the original password. This allows remote unauthenticated attackers to disclose or tamper with PLC configuration and program data.

MitigationIsolate affected PLCs behind firewalls or air-gapped networks to reduce exposure, disable unnecessary remote access protocols, and apply vendor-supplied firmware updates when available. Monitor network traffic for authentication anomalies.

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
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

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

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 the PLC model
    Locate the model label on the physical PLC unit or check the project configuration in GX Works3 software for the connected device model number
    Affected if The model is any of: FX5UC, FX5UC-32MR/DS, FX5UC-32MT/D, FX5UC-32MT/DSS, FX5UJ-24MR/ES, FX5UJ-24MT/ES, FX5UJ-24MT/ESS, or FX5UJ-40MR/ES
  2. Verify network connectivity
    Check if the PLC has an IP address assigned and is reachable over Ethernet by pinging the device or reviewing network settings in GX Works3 under Ethernet port configuration
    Affected if The PLC is assigned an IP address and accessible on the network
  3. Confirm remote access protocol is enabled
    Review the PLC Ethernet settings in GX Works3 to determine if protocols that allow remote authentication (such as MELSEC communication, SLMP, or other Ethernet-based protocols) are enabled in the protocol settings
    Affected if Remote access protocols are enabled and the PLC accepts network authentication requests
  4. Check for exposed authentication
    Inspect network traffic or review access control configurations to determine if the PLC authentication interface is exposed to untrusted networks rather than being isolated behind a firewall or air gap
    Affected if The PLC authentication can be reached from networks outside the trusted control system network

You are affected if you use any of the listed FX5U or FX5UJ PLC models and the device network authentication interface is accessible to untrusted networks.

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

Isolate affected PLCs behind firewalls or air-gapped networks to reduce exposure, disable unnecessary remote access protocols, and apply vendor-supplied firmware updates when available. Monitor network traffic for authentication anomalies.

Fix this in Fx5uc Firmware Scoped from the published advisory
  • Consultation12.0 h
  • Implementation20.0 h
  • Testing16.0 h
  • Review / QA8.0 h
56.0 hours of engineering $9,840
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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-2022-25157 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