CVE-2021-20995
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 the webserver cookies of the web based UI contain user credentials.
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 · moderate confidenceWAGO managed switches store user credentials in web server cookies within their web-based UI. This exposes authentication credentials to client-side access, enabling credential theft through cookie interception, XSS, or unauthorized access to browser/client storage.
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
- 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 WAGO switch modelAccess the device's web-based UI or check the physical device labeling to confirm the model number matches one of the affected variants: 0852 0303, 0852 1305, 0852 1505, or 0852 1305/000 001, or 0852 1505/000 001Affected if The device model matches one of the listed affected models
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Check the installed firmware versionLog into the web-based management interface and navigate to the system information or firmware version page. Compare the displayed 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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Inspect web cookies during authenticationLog into the web UI using a browser's developer tools (F12). Under the Application or Storage tab, examine cookies for the device domain. Look for cookie names or values that contain username, password, or authentication tokens in plaintext or weakly encoded formAffected if User credentials (usernames or passwords) are present in cookie names or values
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Capture and analyze HTTP response headersUse a web proxy or browser developer tools to capture the HTTP response when authenticating or after a successful login. Inspect Set-Cookie headers and the response body for credential data being stored or transmitted in cookiesAffected if The Set-Cookie headers or response body contain authentication credentials
A user is affected if they operate one of the listed WAGO switch models with a firmware version at or below the specified threshold AND their web UI cookies contain exposed credentials.
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 to vendor patched firmware version, rotate all credentials immediately after patching, implement network segmentation to limit exposure to the management interface, and disable cookie-based credential storage if configurable.
- Consultation4.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,120.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20995 — 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-2021-20995 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