Security readout for executives and security teams
Plain-English summary
This vulnerability can let an unauthenticated network attacker disrupt Omron CJ Series PLC communications by overwhelming the Ethernet module with a rapid packet sequence. The known impact is denial of PLC service, not data theft or code execution. In OT environments, loss of PLC service can interrupt production or safety-adjacent operations.
Executive priority
Treat this as a high-priority OT availability risk if Omron CJ Series PLCs support production or critical processes. Prioritize exposure reduction and vendor-guidance review over speculative fixes.
Technical view
CVE-2020-6986 affects all versions of Omron PLC CJ Series. It is classified as CWE-400 and has CVSS 7.5: network-accessible, low complexity, no privileges, no user interaction, availability impact only. The described failure is a service error in the PLC Ethernet module causing PLC service denial.
Likely exposure
Exposure is most likely where Omron CJ Series PLC Ethernet modules are reachable from untrusted, flat, or poorly segmented networks. The source says all versions are affected, but does not identify specific module models, firmware builds, or compensating controls.
Exploitation context
The provided sources do not state active exploitation, and the CVE is not marked KEV. The weakness is still operationally serious because a remote unauthenticated availability attack against PLC communications can cause production disruption.
Researcher notes
Evidence is limited to the CVE description and linked ICS advisory. Do not assume code execution, integrity impact, specific firmware fixes, or active exploitation without additional vendor or CISA detail.
Mitigation direction
- Review CISA and Omron guidance for confirmed remediation or workarounds.
- Restrict network access to CJ Series PLC Ethernet interfaces.
- Segment OT networks from corporate and internet-reachable environments.
- Limit PLC communication paths to authorized engineering and control systems.
- Prepare operational recovery procedures for PLC service-denial events.
Validation and detection
- Inventory Omron CJ Series PLCs and Ethernet modules in use.
- Confirm whether PLC interfaces are reachable from non-OT networks.
- Review firewall and ACL rules protecting PLC communication paths.
- Check operational logs for unexplained PLC Ethernet module service errors.
- Document any vendor-confirmed firmware, configuration, or workaround status.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
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ATT&CK lookup starting points
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CWE-400: Exact CWE lookup
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Open ATT&CK lookupCVE-2020-6986 mapping review
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Open ATT&CK lookup- Severity
- High
- CVSS
- 7.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6CISA-ADPVulnerability scoring details
Base CVSS 3.1 score
7.5HighVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://www.us-cert.gov/ics/advisories/icsa-20-063-03CVE reference, icscert · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Uncontrolled Resource Consumption
Uncontrolled Resource Consumption represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.