CVE-2021-20366
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 · uneditedIBM Cloud Pak for Applications 4.3 is vulnerable to cross-site scripting. This vulnerability allows users to embed arbitrary JavaScript code in the Web UI thus altering the intended functionality potentially leading to credentials disclosure within a trusted session. IBM X-Force ID: 195037.
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 confidenceIBM Cloud Pak for Applications 4.3 contains a cross-site scripting (XSS) vulnerability in its Web UI. Attackers can inject arbitrary JavaScript code through the web interface, potentially allowing credential theft or session hijacking within a trusted user session.
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< 4.3.1CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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 installed IBM Cloud Pak for Applications versionRun 'ibmcloud cr app-list' or check the IBM Cloud Pak console for the installed version number. Alternatively, query the operator deployment: 'kubectl get operandrequest -A | grep applications' and check the associated version metadata.Affected if The installed version is 4.3.x where x is less than 1 (i.e., 4.3.0 or any 4.3 release before 4.3.1)
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Confirm the Web UI component is deployedCheck if the web interface is accessible by querying the ingress or route: 'kubectl get ingress -A' or 'kubectl get route -A' looking for routes associated with the applications console.Affected if The Web UI route or ingress exists and is accessible to users
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Verify the platform is running the vulnerable releaseQuery the ClusterServiceVersion (CSV) for the IBM Cloud Pak for Applications operator: 'kubectl get csv -A | grep ibm-cloudpak-applications' and examine the version field.Affected if The CSV version shows a release prior to 4.3.1
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Check for recent security events in audit logsReview IBM Cloud Pak audit logs for any suspicious JavaScript injection patterns in web requests. Look for unexpected script tags or encoded payloads in user input fields.Affected if Malicious injection patterns are found in web traffic or audit logs
You are affected if IBM Cloud Pak for Applications version 4.3.0 or any pre-4.3.1 release is installed and the Web UI is 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 data4.3.1
Apply the vendor patch or security update from IBM for Cloud Pak for Applications 4.3. Implement output encoding and input validation for all user-supplied data in the Web UI to prevent XSS attacks.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-20366 — 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-2021-20366 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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