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Q03udvcpu FirmwareOperating system · Mitsubishielectric

CVE-2019-6535

HIGH · 7.5 CVSS v3.1 Published 2019-02-05
Fix available
A fix is available. Upgrade to after 20081 or later.
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
Mitsubishi Electric Q03/04/06/13/26UDVCPU: serial number 20081 and prior, Q04/06/13/26UDPVCPU: serial number 20081 and prior, and Q03UDECPU, Q04/06/10/13/20/26/50/100UDEHCPU: serial number 20101 and prior. A remote attacker can send specific bytes over Port 5007 that will result in an Ethernet stack crash and disruption to USB communication.

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

A remote attacker can send specially crafted bytes to Port 5007 on affected Mitsubishi Electric Q-series PLC CPUs (Q03/04/06/13/26UDVCPU, Q04/06/13/26UDPVCPU, Q03UDECPU, Q04/06/10/13/20/26/50/100UDEHCPU), causing the Ethernet stack to crash and disrupting USB communication. This is a network-based denial-of-service vulnerability requiring no authentication.

MitigationIsolate affected PLCs behind network segmentation/firewalls to limit exposure to Port 5007, and apply vendor firmware updates when released. Implement compensating controls such as intrusion detection to monitor for anomalous traffic on port 5007.

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
Q03udvcpu FirmwareOperating system
Affected:<= 20081
Q04udvcpu FirmwareOperating system
Affected:<= 20081
Q06udvcpu FirmwareOperating system
Affected:<= 20081
Q13udvcpu FirmwareOperating system
Affected:<= 20081
Q26udvcpu FirmwareOperating system
Affected:<= 20081
Q04udpvcpu FirmwareOperating system
Affected:<= 20081
Q06udpvcpu FirmwareOperating system
Affected:<= 20081
Q13udpvcpu FirmwareOperating system
Affected:<= 20081

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
    Access the PLC via GX Works2 or GX Developer and check the CPU model type in the system configuration. Alternatively, check the physical label on the CPU module for the model number (e.g., Q03UDVCPU, Q04UDVCPU, Q06UDVCPU, Q13UDVCPU, Q26UDVCPU, Q04UDPVCPU, Q06UDPVCPU, Q13UDPVCPU).
    Affected if The model matches any of these: Q03UDVCPU, Q04UDVCPU, Q06UDVCPU, Q13UDVCPU, Q26UDVCPU, Q04UDPVCPU, Q06UDPVCPU, Q13UDPVCPU, Q03UDECPU, Q04/06/10/13/20/26/50/100UDEHCPU
  2. Check firmware version
    Connect to the PLC using GX Works2, go to the CPU module diagnostics, and retrieve the firmware version. Compare the displayed version number against the affected range.
    Affected if Firmware version is 20081 or lower (the CVE states affected versions are <= 20081)
  3. Verify Ethernet port is configured
    In GX Works2, check the PLC parameter settings for the Ethernet port configuration. Confirm whether the built-in Ethernet port (or Ethernet module) is enabled and assigned an IP address.
    Affected if Ethernet port is enabled and configured with an IP address, making the device network-accessible on port 5007
  4. Check network exposure of Port 5007
    From a workstation on the same network, run a port scan targeting the PLC IP address on port 5007 (e.g., nmap -p 5007 <PLC_IP> or telnet <PLC_IP> 5007). Check if the port responds or is accessible.
    Affected if Port 5007 is open and reachable from an untrusted network segment
  5. Look for crash indicators
    Check the CPU module for error indicators (RUN LED off, ERR LED flashing). In GX Works2, review the CPU error history and event log for recent entries indicating Ethernet stack failures or USB communication disruptions.
    Affected if Recent error logs show Ethernet stack crashes or USB communication failures with timestamps corresponding to potential malicious traffic

Your PLC is affected if it is a Q-series model from the affected list AND has firmware version 20081 or lower AND has Ethernet enabled, exposing port 5007 to the network.

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
Upgrade available Upgrade to a release after 20081
Interim mitigation

Isolate affected PLCs behind network segmentation/firewalls to limit exposure to Port 5007, and apply vendor firmware updates when released. Implement compensating controls such as intrusion detection to monitor for anomalous traffic on port 5007.

Fix this in Q03udvcpu Firmware Scoped from the published advisory
  • Consultation8.0 h
  • Implementation16.0 h
  • Testing12.0 h
  • Review / QA4.0 h
40.0 hours of engineering $7,000
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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-2019-6535 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