CVE-2025-7731
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 · uneditedCleartext Transmission of Sensitive Information vulnerability in Mitsubishi Electric Corporation MELSEC iQ-F Series CPU module allows a remote unauthenticated attacker to obtain credential information by intercepting SLMP communication messages, and read or write the device values of the product and stop the operations of programs by using the obtained credential information.
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 · moderate confidenceThe MELSEC iQ-F Series CPU module transmits SLMP communication messages in cleartext without encryption, allowing a remote unauthenticated attacker to intercept network traffic and obtain credential information. With captured credentials, the attacker can read/write device values and stop program operations.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify the MELSEC iQ-F Series CPU moduleAccess the CPU module via engineering software (e.g., GX Works3) or check the device nameplate/model number on the physical unit. Confirm the model is part of the iQ-F Series (e.g., FX5U, FX5UC, FX5S).Affected if The installed device is a MELSEC iQ-F Series CPU module.
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Check SLMP communication statusIn GX Works3, navigate to the CPU module parameters -> Ethernet port configuration -> SLMP communication settings. Verify if the SLMP function is enabled (SLMP connection facility or SLMP server functionality is turned on).Affected if SLMP communication is enabled on the device.
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Verify SLMP encryption configurationIn the same SLMP settings menu, check whether SSL/TLS encryption is configured for SLMP connections. Look for options such as 'TLS' or 'SSL' and confirm a valid certificate or encryption method is selected.Affected if SLMP is enabled but TLS/SSL encryption is not configured or is set to 'None'.
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Capture and inspect network trafficUse a network packet capture tool (e.g., Wireshark) on the same network segment as the CPU module. Filter for SLMP traffic using protocol filter 'SLMP' or port 5007 (default SLMP port). Examine captured packets for plaintext content including authentication credentials or device data.Affected if Captured SLMP packets contain readable plaintext data including user credentials, device registers, or program commands.
A user is affected if they have a MELSEC iQ-F Series CPU module with SLMP communication enabled and without TLS/SSL encryption, as evidenced by cleartext credentials appearing in captured network traffic.
Generated from the published advisory. Verify against your own configuration.
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 dataImplement encryption for SLMP communications (e.g., TLS/SSL wrapper, VPN tunnel) or apply vendor firmware updates that address the cleartext transmission. Network segmentation can reduce exposure to unauthenticated attackers.
- Consultation8.0 h
- Implementation20.0 h
- Testing12.0 h
- Review / QA6.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-7731 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2025-7731 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- 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
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