CVE-2020-12505
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 · uneditedImproper Authentication vulnerability in WAGO 750-8XX series with FW version <= FW07 allows an attacker to change some special parameters without authentication. This issue affects: WAGO 750-852, WAGO 750-880/xxx-xxx, WAGO 750-881, WAGO 750-831/xxx-xxx, WAGO 750-882, WAGO 750-885/xxx-xxx, WAGO 750-889 in versions FW07 and below.
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 confidenceWAGO 750-8XX series PLCs (750-852, 750-880/881/882, 750-831, 750-885, 750-889) running firmware FW07 and below contain an improper authentication flaw that allows unauthenticated attackers to modify certain special system parameters. This bypass of authentication controls enables unauthorized configuration changes on affected industrial controllers.
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<= fw07<= fw07<= fw07<= fw07<= fw07<= fw07<= fw07CVSS 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
- None
- Integrity
- Low
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/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 WAGO PLC modelLocate the device identification through its web interface, device label, or network inventory. Confirm the model number is one of: 750-852, 750-880, 750-881, 750-882, 750-831, 750-885, or 750-889.Affected if The device is any of these seven model numbers.
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Determine the firmware versionAccess the PLC web interface (typically via HTTP/HTTPS) and navigate to the System > Firmware or Device Information section to read the installed firmware version.Affected if The firmware version is FW07 or any version number lower than FW07.
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Assess network accessibility of the management interfaceCheck if the PLC web-based management interface (ports 80/443 or custom HTTP/HTTPS ports) is reachable from networks outside the trusted operational technology (OT) network, such as the corporate IT network or the internet.Affected if The management interface is exposed to untrusted networks without firewall filtering.
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Review configuration change logsExamine the PLC's event logs or audit logs for any unauthorized or unexpected modifications to special system parameters, particularly changes made without valid authentication credentials.Affected if Unexpected configuration changes appear in logs without corresponding legitimate administrative activity.
A WAGO 750-8XX PLC is affected if it is model 750-852, 750-880, 750-881, 750-882, 750-831, 750-885, or 750-889 running firmware FW07 or below, and its management interface is network-accessible.
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 dataUpdate WAGO 750-8XX devices to firmware version FW08 or higher to patch the authentication bypass. If immediate patching is not feasible, restrict network access to PLCs via firewalls or VLANs and monitor for unauthorized configuration changes.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-12505 — 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-2020-12505 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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