CVE-2021-32978
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 · uneditedThe programming protocol allows for a previously entered password and lock state to be read by an attacker. If the previously entered password was successful, the attacker can then use the password to unlock Automation Direct CLICK PLC CPU Modules: C0-1x CPUs with firmware prior to v3.00.
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 confidenceThis is an information disclosure vulnerability in the programming protocol of Automation Direct CLICK PLC C0-1x CPU modules. An attacker can read previously entered passwords and lock states from the device memory. If a password was successfully entered before, the attacker can reuse that password to unlock the PLC, bypassing authentication controls.
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< 3.00< 3.00< 3.00< 3.00< 3.00< 3.00< 3.00< 3.00CVSS 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
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
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 PLC model numberLocate the model number label on the CLICK PLC C0-1x CPU module. The model number should be formatted like C0-10dd1e-D, C0-10dd2e-D, C0-10dre-D, C0-10are-D, C0-11dd1e-D, C0-11dd2e-D, C0-11dre-D, or C0-11are-D.Affected if The model number matches one of the affected variants: C0-10dd1e, C0-10dd2e, C0-10dre, C0-10are, C0-11dd1e, C0-11dd2e, C0-11dre, or C0-11are.
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Check the installed firmware versionAccess the PLC through its programming software (CLICK Programming Software) or via the device's built-in web interface if available. Navigate to the system information or firmware version display. The firmware version is typically shown in the CPU module properties or system status screen.Affected if The firmware version is less than 3.00 (for example, 2.xx or earlier).
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Verify the programming protocol exposureDetermine if the PLC programming port (typically Ethernet port for network-connected models) is accessible from untrusted networks. Check network firewall rules, VLAN configurations, and access control lists that govern traffic to the PLC's IP address on the programming protocol port.Affected if The programming protocol port is reachable from network segments that contain untrusted or non-privileged users.
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Review password configuration historyExamine whether any passwords have been set and entered on the PLC. Check the PLC project file for lock state configuration. Note that the vulnerability exploits previously entered passwords stored in memory, so the risk is higher if passwords were entered and then changed or if the PLC was unlocked.Affected if Password protection has been configured on the PLC and passwords were entered at least once.
The environment is affected if the PLC model is one of the C0-1x variants and the firmware version is below 3.00, with the programming protocol accessible from accessible network segments.
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 · scoped3.00
Upgrade CLICK PLC C0-1x CPU firmware to v3.00 or later to address this vulnerability. If immediate patching is not possible, network segmentation and access controls should be implemented to limit exposure to untrusted networks.
Firmware v3.00 or later for Automation Direct CLICK PLC C0-1x CPU modules
- 1. Identify the specific CLICK PLC model (C0-10dd1e D, C0-10dd2e D, C0-10dre D, C0-10are D, C0-11dd1e D, C0-11dd2e D, C0-11dre D, or C0-11are D) from the affected units
- 2. Download the latest firmware version 3.00 or later from the official Automation Direct website at www.automationdirect.com
- 3. Review Automation Direct CLICK PLC firmware upgrade documentation for proper procedures
- 4. Establish a direct, isolated network connection to the PLC for firmware update (do not update over production networks)
- 5. Use the appropriate programming software (CLICK Programming Software) to upload the new firmware to the CPU module
- 6. After firmware update, verify the PLC is operating normally and confirm the new firmware version is installed
- 7. As a security best practice, change the CPU password after the upgrade to ensure no previously compromised credentials remain in use
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-32978 — 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-2021-32978 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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