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NVD / CVE Program· CNA jpcert

CVE-2023-38744: Denial-of-service (DoS) vulnerability due to improper validation of specified type of input issue exists in the built-in EtherNet/IP port of

Noroxi assessment

Priority: Monitor (action score 30/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.86% (FIRST EPSS); higher than 58.6% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Denial-of-service (DoS) vulnerability due to improper validation of specified type of input issue exists in the built-in EtherNet/IP port of the CJ Series CJ2 CPU unit and the communication function of the CS/CJ Series EtherNet/IP unit. If an affected product receives a packet which is specially crafted by a remote unauthenticated attacker, the unit of the affected product may fall into a denial-of-service (DoS) condition. Affected products/versions are as follows: CJ2M CPU Unit CJ2M-CPU3[] Unit version of the built-in EtherNet/IP section Ver. 2.18 and earlier, CJ2H CPU Unit CJ2H-CPU6[]-EIP Unit version of the built-in EtherNet/IP section Ver. 3.04 and earlier, CS/CJ Series EtherNet/IP Unit CS1W-EIP21 V3.04 and earlier, and CS/CJ Series EtherNet/IP Unit CJ1W-EIP21 V3.04 and earlier.

HighCVSS 7.5 · v3.1—No exploit No fix recorded
Published
Aug 3, 2023
Updated
Jun 17, 2026
EPSS
0.8% · 58th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2023-38744

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
omroncj2m-cpu35 firmware
omroncj2m-cpu35
omroncj2m-cpu34 firmware
omroncj2m-cpu34
omroncj2m-cpu33 firmware
omroncj2m-cpu33
omroncj2m-cpu32 firmware
omroncj2m-cpu32
omroncj2m-cpu31 firmware
omroncj2m-cpu31
omroncj2h-cpu68-eip firmware
omroncj2h-cpu68-eip

and 12 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • omron cj1w-eip21 firmwareup to 3.04 inclusive
  • omron cj2h-cpu64-eip firmwareup to 3.04 inclusive
  • omron cj2h-cpu65-eip firmwareup to 3.04 inclusive
  • omron cj2h-cpu66-eip firmwareup to 3.04 inclusive
  • omron cj2h-cpu67-eip firmwareup to 3.04 inclusive
  • omron cj2h-cpu68-eip firmwareup to 3.04 inclusive
  • omron cj2m-cpu31 firmwareup to 2.18 inclusive
  • omron cj2m-cpu32 firmwareup to 2.18 inclusive
  • omron cj2m-cpu33 firmwareup to 2.18 inclusive
  • omron cj2m-cpu34 firmwareup to 2.18 inclusive
  • omron cj2m-cpu35 firmwareup to 2.18 inclusive
  • omron cs1w-eip21 firmwareup to 3.04 inclusive

Versions reported by the vendor

Affected version ranges reported by the assigning authority (jpcert). Independent of NVD's CPE analysis and usually ahead of it.

  • OMRON Corporation CJ2H CPU Unit

    • CJ2H-CPU6[]-EIP Unit version of the built-in EtherNet/IP section Ver. 3.04 and earlieraffected

  • OMRON Corporation CJ2M CPU Unit

    • CJ2M-CPU3[] Unit version of the built-in EtherNet/IP section Ver. 2.18 and earlieraffected

  • OMRON Corporation CS/CJ Series EtherNet/IP Unit

    • CS1W-EIP21 V3.04 and earlier, CJ1W-EIP21 V3.04 and earlieraffected

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-1284 · Improper Validation of Specified Quantity in Input

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records