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Q03udecpu FirmwareOperating system · Mitsubishielectric

CVE-2022-24946

HIGH · 7.5 CVSS v3.1 Published 2022-06-15
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
84/100
Remediation priority · High
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
Improper Resource Locking vulnerability in Mitsubishi Electric MELSEC iQ-R Series R12CCPU-V firmware versions "16" and prior, Mitsubishi Electric MELSEC-Q Series Q03UDECPU the first 5 digits of serial No. "24061" and prior, Mitsubishi Electric MELSEC-Q Series Q04/06/10/13/20/26/50/100UDEHCPU the first 5 digits of serial No. "24061" and prior, Mitsubishi Electric MELSEC-Q Series Q03/04/06/13/26UDVCPU the first 5 digits of serial number "24051" and prior, Mitsubishi Electric MELSEC-Q Series Q04/06/13/26UDPVCPU the first 5 digits of serial number "24051" and prior, Mitsubishi Electric MELSEC-Q Series Q12DCCPU-V all versions, Mitsubishi Electric MELSEC-Q Series Q24DHCCPU-V(G) all versions, Mitsubishi Electric MELSEC-Q Series Q24/26DHCCPU-LS all versions, Mitsubishi Electric MELSEC-L series L02/06/26CPU(-P) the first 5 digits of serial number "24051" and prior, Mitsubishi Electric MELSEC-L series L26CPU-(P)BT the first 5 digits of serial number "24051" and prior and Mitsubishi Electric MELIPC Series MI5122-VW firmware versions "05" and prior allows a remote unauthenticated attacker to cause a denial of service (DoS) condition in Ethernet communications by sending specially crafted packets. A system reset of the products is required for recovery.

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

An improper resource locking vulnerability in Mitsubishi Electric MELSEC PLCs (iQ-R, Q, L series and MIIPC) allows remote unauthenticated attackers to send specially crafted Ethernet packets that cause a denial of service condition. The vulnerability stems from inadequate locking mechanisms when handling network traffic, leading to resource exhaustion or deadlock. Recovery requires a manual system reset of the affected device.

MitigationUpdate affected PLC firmware to versions beyond those specified (R12CCPU-V version "17" or later, Q03UDECPU serial beyond "24061", etc.). As an interim compensating control, implement network segmentation and firewall rules to restrict unauthorized Ethernet 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
Q03udecpu FirmwareOperating system
Affected:all versions
Q04udehcpu FirmwareOperating system
Affected:all versions
Q04udpvcpu FirmwareOperating system
Affected:all versions
Q04udvcpu FirmwareOperating system
Affected:all versions
Q100udehcpu FirmwareOperating system
Affected:all versions
Q50udehcpu FirmwareOperating system
Affected:all versions
Q26dhccpu Ls FirmwareOperating system
Affected:all versions
Q26udehcpu 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
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/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
    Use Mitsubishi programming software (GX Works3, GX Developer) to query the CPU module, or physically inspect the PLC hardware label to determine the exact model number
    Affected if The model matches Q03UDECPU, Q04UDEHCPU, Q04UDPVCPU, Q04UDVCPU, Q100UDEHCPU, Q50UDEHCPU, Q26DHCCPU-LS, or Q26UDEHCPU
  2. Verify firmware version
    Connect to the PLC via Mitsubishi programming software and navigate to the CPU module diagnostics to read the firmware version string
    Affected if The PLC model is one of the affected models - all firmware versions are vulnerable
  3. Check network exposure
    Review network architecture diagrams and firewall rules to determine if the PLC Ethernet port (MELSEC protocol port 5000/5001 or direct IP access) is accessible from untrusted or outside networks
    Affected if The PLC is reachable from network segments outside the industrial zone without firewall filtering
  4. Inspect device availability
    Attempt to communicate with the PLC via ping, MELSEC protocol queries, or programming software connection to verify it is responsive
    Affected if The PLC is unresponsive, hangs during communication attempts, or requires manual power cycle to recover - indicating potential exploitation
  5. Review network logs for suspicious Ethernet traffic
    Analyze network traffic captures or IDS/IPS logs for unusual MELSEC protocol packets, especially from unauthenticated sources or malformed packets targeting port 5000/5001
    Affected if Traffic logs show malformed Ethernet packets from unexpected sources targeting the PLC

You are affected if you have any of the listed PLC models (Q03UDECPU, Q04UDEHCPU, Q04UDPVCPU, Q04UDVCPU, Q100UDEHCPU, Q50UDEHCPU, Q26DHCCPU-LS, or Q26UDEHCPU) connected to a network where unauthenticated Ethernet access is possible.

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.

dbcve · scoped
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update affected PLC firmware to versions beyond those specified (R12CCPU-V version "17" or later, Q03UDECPU serial beyond "24061", etc.). As an interim compensating control, implement network segmentation and firewall rules to restrict unauthorized Ethernet access to the industrial network.

Recommended fix Moderate confidence

Mitsubishi Electric MELSEC iQ-R R12CCPU-V firmware version 17 or later; MELSEC-Q Series Q03UDECPU/Q04/06/10/13/20/26/50/100UDEHCPU serial number 24062 or later; Q03/04/06/13/26UDVCPU and Q04/06/13/26UDPVCPU serial number 24052 or later; MELSEC-L series L02/06/26CPU(-P)/L26CPU-(P)BT serial number 240

  1. 1. Identify the specific model and current firmware version/serial number of the affected Mitsubishi Electric PLC device.
  2. 2. Navigate to the official Mitsubishi Electric support page for MELSEC series products to obtain firmware updates.
  3. 3. Download the appropriate firmware update for the specific model (e.g., for R12CCPU-V, obtain firmware version "17" or later; for Q03UDECPU/Q04UDEHCPU, obtain version with serial number "24062" or later; for Q03/04/06/13/26UDVCPU and Q04/06/13/26UDPVCPU, obtain version with serial number "24052" or later; for L-series CPUs, obtain version with serial number "24052" or later; for MI5122-VW, obtai
  4. 4. Follow the manufacturer's firmware update procedure documented in the MELSEC iQ-R or MELSEC-Q programming manual to apply the update.
  5. 5. After updating, verify the firmware version has been successfully applied.
  6. 6. Test normal Ethernet communication operations to confirm the DoS vulnerability is remediated.
  7. 7. Implement network segmentation and firewall rules to limit exposure to unauthenticated remote attackers as an additional compensating control.
Caveat Firmware updates on PLCs may require reprogramming of associated HMI and SCADA systems; ensure backup of PLC programs before updating and test thoroughly in non-production environment

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Q03udecpu Firmware Scoped from the published advisory
  • Consultation6.0 h
  • Implementation8.0 h
  • Testing8.0 h
  • Review / QA4.0 h
26.0 hours of engineering $4,560
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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-2022-24946 in production — separate from our analysis above.

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