CVE-2023-4562
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 · uneditedImproper Authentication vulnerability in Mitsubishi Electric Corporation MELSEC-F Series main modules allows a remote unauthenticated attacker to obtain sequence programs from the product or write malicious sequence programs or improper data in the product without authentication by sending illegitimate messages.
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 confidenceThis is an improper authentication vulnerability in Mitsubishi Electric MELSEC-F Series PLC main modules. The vulnerability allows remote unauthenticated attackers to send illegitimate messages to obtain (read) sequence programs or write malicious sequence programs and improper data, achieving full confidentiality and integrity compromise without any credentials.
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
- High
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 PLC modelLocate the physical device or check network inventory for Mitsubishi Electric MELSEC-F Series PLCs. Look for model numbers FX3G-14MR/DS, FX3G-14MR/ES, FX3G-14MT/DS, FX3G-14MT/DSS, FX3G-14MT/ES, or FX3G-14MT/ESS.Affected if The device matches one of the FX3G 14-point models listed in the affected products.
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Confirm firmware versionAccess the PLC via GX Works2 or GX Developer programming software, or check the unit's nameplate for the firmware version designation.Affected if The firmware version is present (all versions of the listed models are affected).
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Check network accessibilityDetermine if the PLC Ethernet port is connected to the network and reachable from untrusted networks. Use network scans to identify open ports, particularly ports 5000-5002 (MC protocol) or 1025 (SLMP).Affected if The PLC is network-connected and accessible from networks outside the trusted control system zone.
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Verify MELSEC protocol exposureAttempt to send an unauthenticated MELSEC protocol query to the PLC's IP address on the Ethernet port using tools like a raw TCP client or protocol analyzer.Affected if The PLC responds to MELSEC protocol requests without requiring authentication credentials.
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Inspect for unauthorized program changesCompare the current sequence program in the PLC with known-good backups using GX Works2 or by reading the program via the MELSEC protocol.Affected if The program contents differ from the expected baseline or show unauthorized modifications.
A user is affected if they have a Mitsubishi Electric MELSEC-F Series FX3G-14 PLC (any firmware version) with network connectivity where the MELSEC protocol is exposed without authentication controls.
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-supplied firmware updates or patches when available; meanwhile, isolate affected devices behind firewalls, restrict network access to trusted IPs only, and implement monitoring for suspicious MELSEC protocol traffic.
- Consultation8.0 h
- Implementation12.0 h
- Testing16.0 h
- Review / QA8.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-4562 — 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-2023-4562 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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