CVE-2020-13238
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 · uneditedMitsubishi MELSEC iQ-R Series PLCs with firmware 33 allow attackers to halt the industrial process by sending an unauthenticated crafted packet over the network, because this denial of service attack consumes excessive CPU time. After halting, physical access to the PLC is required in order to restore production.
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 confidenceMitsubishi MELSEC iQ-R Series PLCs with firmware 33 contain a denial of service vulnerability where unauthenticated attackers can send a crafted packet over the network that consumes excessive CPU time, causing the PLC to halt the industrial process. Recovery requires physical access to the PLC.
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<= 7<= 7<= 7<= 39<= 39<= 39<= 39<= 39CVSS 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 checksWork through these to decide whether this CVE applies to you.
-
Identify PLC modelLocate the model number on the PLC hardware or in the engineering software (GX Works3) under CPU module information. Confirm it is one of: R00CPU, R01CPU, R02CPU, R04CPU, R08CPU, R16CPU, R32CPU, or R120CPU.Affected if The PLC model matches one of the eight affected models listed in the CVE.
-
Check firmware versionAccess the PLC via GX Works3 or the PLC's web interface to view the firmware version. Navigate to CPU Module -> Product Information -> Firmware Version.Affected if The firmware version is less than or equal to 7 for R00CPU/R01CPU/R02CPU, or less than or equal to 39 for R04CPU/R08CPU/R16CPU/R32CPU/R120CPU.
-
Verify network accessibilityCheck if the PLC has an IP address configured and is reachable over the network. Use ping or check network configuration in GX Works3 under Connection Destination settings.Affected if The PLC is network-accessible from untrusted network segments, as the attack requires sending crafted packets over the network.
-
Review network exposureExamine firewall rules, VLAN configurations, and network segmentation to determine if the PLC is exposed to untrusted network traffic. Check if UDP/TCP ports used by MELSEC protocols (such as 5000-5002, 5007, 4520, 4521) are open to untrusted hosts.Affected if The PLC has open network ports accessible from untrusted or unauthorized network segments.
A user is affected if their PLC is one of the eight listed models, runs firmware at or below the specified version limits, and is accessible over a network where unauthenticated attackers could send crafted packets.
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 network segmentation and firewall rules to restrict unauthorized access to the PLC, and investigate firmware updates from Mitsubishi that may address this vulnerability.
- Consultation8.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,608.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-13238 — 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-2020-13238 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
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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