CVE-2023-4699
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 · uneditedMissing Authentication for Critical Function vulnerability in Mitsubishi Electric Corporation MELSEC-F Series CPU modules, MELSEC iQ-F Series, MELSEC iQ-R series CPU modules, MELSEC iQ-R series, MELSEC iQ-L series, MELSEC Q series, MELSEC-L series, Mitsubishi Electric CNC M800V/M80V series, Mitsubishi Electric CNC M800/M80/E80 series and Mitsubishi Electric CNC M700V/M70V/E70 series allows a remote unauthenticated attacker to execute arbitrary commands by sending specific packets to the affected products. This could lead to disclose or tamper with information by reading or writing control programs, or cause a denial-of-service (DoS) condition on the products by resetting the memory contents of the products to factory settings or resetting the products remotely.
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 confidenceMissing authentication in Mitsubishi Electric MELSEC-F, iQ-F, iQ-R, iQ-L, Q, L series PLCs and M800V/M80V, M800/M80/E80, M700V/M70V/E70 CNC series allows remote unauthenticated attackers to send specific packets executing arbitrary commands, enabling reading/writing of control programs or triggering factory/remote resets causing DoS.
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 dataall versionsall versionsall versionsall versionsall versionsall versionsall versionsall versionsCVSS 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
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify MELSEC-F PLCs on the networkScan the network for Mitsubishi MELSEC-F series PLCs using service detection or by checking for Mitsubishi-specific protocols on common industrial ports. Document the IP addresses and hostnames of any found devices.Affected if Any Fx3u series PLC (models 16mt/es, 16mr/es, 32mt/es, 32mr/es, 48mt/es, 64mt/es, 80mt/es, 128mt/e) is found on the network and reachable from any network segment.
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Verify the specific PLC modelAccess the PLC or its programming software (GX Works2 or GX Works3) and confirm the exact model number matches one of the affected variants: Fx3u-16mt/es, Fx3u-16mr/es, Fx3u-32mt/es, Fx3u-32mr/es, Fx3u-48mt/es, Fx3u-64mt/es, Fx3u-80mt/es, or Fx3u-128mt/e.Affected if The installed PLC model is any of the Fx3u variants listed in the affected products.
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Assess network exposure of the PLCReview firewall rules, network segmentation, and access control lists to determine if the PLC is accessible from network segments that contain untrusted or external devices (including the internet, guest networks, or demilitarized zones).Affected if The PLC has any routable network path from untrusted/external IP addresses or network segments without proper firewall filtering.
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Confirm no authentication is required for PLC commandsUsing a protocol analyzer or network capture tool, observe whether the PLC responds to MELSEC protocol commands without requiring any authentication handshake or credential exchange. This can be done by sending a simple status query packet to the PLC and observing the response.Affected if The PLC responds to protocol commands without any authentication token, session establishment, or credential challenge.
A user is affected if they have any Fx3u series PLC (16mt/es, 16mr/es, 32mt/es, 32mr/es, 48mt/es, 64mt/es, 80mt/es, or 128mt/e) exposed to network segments that are not fully trusted, since the vulnerability allows remote unauthenticated attackers to execute arbitrary commands.
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 dataApply vendor firmware updates for all affected PLC and CNC product series; until patched, implement network segmentation, firewalls, and deny untrusted external access to industrial control networks.
- Consultation16.0 h
- Implementation24.0 h
- Testing20.0 h
- Review / QA8.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-4699 — 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-2023-4699 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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- Version or environment caveats, and links to real fixes
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