CVE-2021-20998
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 multiple managed switches by WAGO in different versions without authorization and with specially crafted packets it is possible to create users.
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 managed switches contain an authentication bypass vulnerability allowing unauthenticated attackers to create new administrative users via specially crafted network packets. This grants attackers full administrative control over affected switches without any credentials.
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<= 1.2.3.s0<= 1.1.7.s0<= 1.1.6.s0<= 1.0.4.s0<= 1.0.4.s0CVSS 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 WAGO switch modelCheck the device model number on the physical switch label or via SNMP/sysinfo queries. Look for model numbers 0852 0303, 0852 1305, 0852 1505, or their /000 001 variants.Affected if The device is a WAGO 0852 series managed switch.
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Check firmware versionAccess the switch management interface (web UI or CLI) and navigate to System > Firmware or use 'show version' command. Compare the installed firmware version against the affected ranges: 0852 0303 <= 1.2.3.s0, 0852 1305 <= 1.1.7.s0, 0852 1505 <= 1.1.6.s0, 0852 1305/000 001 <= 1.0.4.s0, 0852 1505/000 001 <= 1.0.4.s0Affected if The firmware version is at or below the specified threshold for your model.
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Audit administrative accountsIn the switch management interface, go to User Management or Administration > Users. Review all accounts with administrative privileges. Compare against known legitimate administrators.Affected if There are administrative accounts present that were not created by authorized personnel.
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Verify management interface exposureReview network configuration to determine if the switch management interface (HTTP, HTTPS, SSH, or telnet) is accessible from untrusted networks or the internet.Affected if Management interfaces are reachable from untrusted networks.
If the device is a WAGO 0852 series switch running firmware at or below the affected version threshold and has unauthorized admin accounts, the environment is likely affected or has been compromised.
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 dataIsolate management interfaces from untrusted networks, apply vendor firmware updates when available, audit switch configurations for unauthorized accounts, and implement network segmentation for operational technology assets.
- Consultation8.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $10,240.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20998 — 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-2021-20998 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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A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- 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
- No spam, self-promotion, credentials, or personal data