dbcve.org
Fx5uc FirmwareOperating system · Mitsubishielectric

CVE-2022-25156

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 Weak Hash 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 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 using a password reversed from a previously 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 stems from the use of a weak hashing algorithm for password storage in Mitsubishi Electric MELSEC PLCs. An attacker who has eavesdropped on a password hash can reverse it to obtain the plaintext password and then use those credentials to authenticate to the device remotely without any other information.

MitigationApply vendor-provided firmware patches when available, implement network segmentation to limit exposure of affected PLCs to untrusted networks, and consider additional authentication controls such as VPN access to the industrial network.

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 the PLC model
    Use the vendor engineering software (GX Works3) or physically inspect the PLC unit to confirm the exact model number matches one of the affected models: FX5UC, FX5UC-32MR/DS, FX5UC-32MT/D, FX5UC-32MT/DSS, FX5UJ-24MR/ES, FX5UJ-24MT/ES, FX5UJ-24MT/ESS, or FX5UJ-40MR/ES
    Affected if The model matches any of the listed affected products
  2. Verify the firmware version
    Connect to the PLC via GX Works3, navigate to the CPU module properties, and read the firmware version field
    Affected if All firmware versions are affected, so any version confirms exposure
  3. Confirm password-based authentication is in use
    Check the PLC project settings in GX Works3 under the CPU module security settings, or examine network traffic to determine if password authentication is being used for remote access
    Affected if Password-based authentication is enabled or remote password-based access is observed in network traffic

If the PLC is any of the FX5UC or FX5UJ models and password-based authentication is enabled or in use, the environment is affected by this weak password hashing vulnerability.

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

Apply vendor-provided firmware patches when available, implement network segmentation to limit exposure of affected PLCs to untrusted networks, and consider additional authentication controls such as VPN access to the industrial network.

Fix this in Fx5uc Firmware Scoped from the published advisory
  • Consultation12.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA8.0 h
48.0 hours of engineering $8,520
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $13,632.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2022-25156 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.

Get it on GitHub Scan in the browser

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-2022-25156 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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