Fx5uc FirmwareOperating system · Mitsubishielectric

CVE-2022-25159

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
Authentication Bypass by Capture-replay 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 RJ72GF15-T2 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 and Mitsubishi Electric MELSEC Q series QJ71E71-100 all versions allows a remote unauthenticated attacker to login to the product by replay attack.

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 capture-replay authentication bypass vulnerability affecting multiple Mitsubishi Electric MELSEC PLC series (iQ-F, iQ-R, and Q series). An attacker can capture valid authentication credentials or session tokens during a legitimate session and replay them to bypass authentication and gain unauthorized remote access to the affected devices.

MitigationApply vendor-supplied firmware updates when available. In the interim, network segmentation and restricting access to trusted IP addresses only can reduce exposure to remote attackers.

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 affected MELSEC PLC models on the network
    Inventory network devices to locate Mitsubishi Electric MELSEC PLCs, specifically the FX5uc and FX5uj series models listed in the CVE (FX5uc, FX5uc 32mr/ds, FX5uc 32mt/d, FX5uc 32mt/dss, FX5uj 24mr/es, FX5uj 24mt/es, FX5uj 24mt/ess, FX5uj 40mr/es). Use network scanning tools or asset management databases to find these devices.
    Affected if Any of the listed FX5uc or FX5uj PLC models are present on the network.
  2. Verify device is network accessible
    Check if the identified PLC devices have active Ethernet or MELSOFT communication ports open (typically port 5007 for MELSOFT). Use network scanning to determine if the device accepts remote connections.
    Affected if The PLC device accepts remote network connections on MELSOFT or Ethernet ports.
  3. Assess network exposure of PLC devices
    Review firewall rules, access control lists, and network segmentation to determine if the PLC is accessible from untrusted networks or the internet. Check if the device is directly exposed or behind adequate access controls.
    Affected if The PLC is accessible from untrusted networks or the internet without IP-based access restrictions.
  4. Confirm authentication method in use
    Determine if the PLC uses standard MELSOFT authentication or session-based authentication without replay protection. Review device configuration and communication logs for authentication patterns.
    Affected if The device uses standard authentication that does not implement replay protection or session token randomization.

A user is affected if they have any of the listed Mitsubishi Electric FX5uc or FX5uj PLC models exposed to network access where captured credentials or session tokens could be replayed by an attacker.

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-supplied firmware updates when available. In the interim, network segmentation and restricting access to trusted IP addresses only can reduce exposure to remote attackers.

Fix this in Fx5uc Firmware Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing12.0 h
  • Review / QA4.0 h
28.0 hours of engineering $4,760
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Scan for this in your stack

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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-2022-25159 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
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  • Version or environment caveats, and links to real fixes
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