CVE-2019-18261
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 · uneditedIn Omron PLC CS series, all versions, Omron PLC CJ series, all versions, and Omron PLC NJ series, all versions, the software does not implement sufficient measures to prevent multiple failed authentication attempts within in a short time frame, making it more susceptible to brute force attacks.
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 confidenceOmron PLC CS, CJ, and NJ series lack brute force protection mechanisms, allowing unlimited failed authentication attempts without account lockout, rate limiting, or temporary blocking. An attacker can systematically guess credentials until successful, potentially gaining full control of 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 dataall 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
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/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 if you have an Omron PLCLocate PLC devices on your network - check network inventory, device labels, or engineering documentation for Omron CS, CJ, or NJ series PLCsAffected if You have an Omron CS, CJ, or NJ series PLC in your environment
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Confirm PLC network accessibilityCheck if the PLC has an IP address and is reachable over the network (ping, port scan, or check network diagrams)Affected if The PLC is accessible on the network with an IP address
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Verify if network rate limiting existsReview firewall, IPS, or network infrastructure rules protecting the PLC. Check if authentication attempts are rate-limited or throttled from external sourcesAffected if No network-based rate limiting, account lockout, or authentication throttling is configured on network devices protecting the PLC
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Check for authentication protection on the PLCConsult PLC documentation or try a few authentication attempts (in a test environment only) to observe if the device locks out or delays after failed attemptsAffected if The PLC allows unlimited failed authentication attempts without lockout, delay, or temporary blocking
If you have an Omron CS, CJ, or NJ series PLC accessible on the network and no rate limiting or account lockout is enforced at the network or device level, your environment is affected by this vulnerability.
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-based rate limiting or authentication throttling on network infrastructure (firewalls/IPS) protecting the PLCs. If supported by firmware, enable built-in account lockout policies. Consider placing PLCs behind a jump host with strong authentication.
- Consultation6.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2019-18261 — 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-2019-18261 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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