CVE-2017-16740
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 · uneditedA Buffer Overflow issue was discovered in Rockwell Automation Allen-Bradley MicroLogix 1400 Controllers, Series B and C Versions 21.002 and earlier. The stack-based buffer overflow vulnerability has been identified, which may allow remote code execution.
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 confidenceA stack-based buffer overflow vulnerability exists in Rockwell Automation Allen-Bradley MicroLogix 1400 Controllers (Series B and C, version 21.002 and earlier). The overflow can be triggered remotely, potentially allowing an attacker to execute arbitrary code on the controller.
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<= 21.002<= 21.002<= 21.002<= 21.002<= 21.002<= 21.002CVSS 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
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:C/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 the controller model numberLocate the physical controller label on the device, or use RSLinx Classic software to browse the network and identify the connected MicroLogix 1400 controller. The model number should be one of: 1766-L32BXBA, 1766-L32AWA, 1766-L32BXB, 1766-L32BWAA, 1766-L32AWAA, or 1766-L32BWA.Affected if The model number matches one of the six affected variants listed.
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Determine the controller seriesCheck whether the controller is Series B or Series C. This information is typically visible on the physical device label, in RSLinx under the controller properties, or via the web interface if enabled.Affected if The controller is identified as Series B or Series C.
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Check the installed firmware versionRetrieve the firmware version from the controller. This can be done through: (1) the LCD display on the controller (navigate to the controller status screen), (2) RSLinx Classic - right-click the controller and view device properties, (3) the built-in web server if it has been enabled, or (4) BOOTP server logs showing the controller's bootp response.Affected if The firmware version is 21.002 or lower.
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Verify network accessibilityDetermine if the controller is accessible over the network via Ethernet/IP. Attempt to ping the controller IP address and verify that EtherNet/IP communication is possible from your workstation using RSLinx or a similar tool.Affected if The controller is network-accessible and the firmware version is 21.002 or earlier.
You are affected if you have a MicroLogix 1400 controller matching one of the listed model numbers, running Series B or C firmware version 21.002 or earlier, and the device is accessible on your network.
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.
dbcve · scopedUpdate MicroLogix 1400 firmware to a version beyond 21.002 when available, and restrict network access to the controllers using network segmentation and firewalls to reduce attack surface.
Firmware version later than 21.002 (contact Rockwell Automation for the specific patched release)
- Identify the exact controller model (1766 L32bxba, L32awa, L32bxb, L32bwaa, L32awaa, or L32bwa) from the MicroLogix 1400 Series B or C line
- Contact Rockwell Automation technical support or visit the official support portal to obtain the security firmware update that addresses CVE-2017-16740
- Backup the current controller configuration before performing any firmware update
- Follow Rockwell Automation's official firmware update procedure for MicroLogix 1400 controllers using their recommended programming software (e.g., RSLogix 500, FactoryTalk Asset Manager)
- Verify the firmware version after update matches the patched release version
- Test the controller functionality and validate that the buffer overflow vulnerability is no longer exploitable
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation8.0 h
- Implementation4.0 h
- Testing6.0 h
- Review / QA4.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2017-16740 — 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-2017-16740 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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- Version or environment caveats, and links to real fixes
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