KnoxApplication · Apache
CVE-2021-42357
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 · uneditedWhen using Apache Knox SSO prior to 1.6.1, a request could be crafted to redirect a user to a malicious page due to improper URL parsing. A request that included a specially crafted request parameter could be used to redirect the user to a page controlled by an attacker. This URL would need to be presented to the user outside the normal request flow through a XSS or phishing campaign.
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 confidenceApache Knox SSO prior to version 1.6.1 contains an open redirect vulnerability caused by improper URL parsing. Attackers can craft specially crafted request parameters to force redirects to attacker-controlled domains. Successful exploitation requires social engineering (XSS or phishing) to convince users to click the malicious link.
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
KnoxApplication
< 1.6.1CVSS 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
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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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Confirm Apache Knox SSO is deployedLocate the Apache Knox installation and verify the SSO component is present in the environmentAffected if Apache Knox SSO is deployed and in use
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Determine the installed Apache Knox versionIdentify the version of the installed Apache Knox SSO by checking the installed binaries, package metadata, or using available version diagnostic commands. Compare the version number against the affected range of versions prior to 1.6.1Affected if The installed version is less than 1.6.1
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Verify SSO functionality is enabledInspect the Knox configuration files or topology settings to confirm the SSO endpoint is configured and actively in useAffected if SSO is enabled and accessible to end users
The environment is affected if Apache Knox SSO is deployed with a version number below 1.6.1 and the SSO component is enabled and 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.
dbcve · scoped1.6.1
Upgrade Apache Knox SSO to version 1.6.1 or later to resolve the improper URL parsing vulnerability.
1.6.1
- 1. Back up your current Apache Knox installation and configuration directory (typically found at {KNOX_HOME}/conf)
- 2. Download Apache Knox version 1.6.1 or later from the official Apache repository (https://knox.apache.org/)
- 3. Stop the running Knox service
- 4. Replace the existing Knox installation directory with the new version 1.6.1 binaries
- 5. Restore your existing configuration files to the new installation's conf directory
- 6. Verify the Knox SSO configuration files for any necessary updates between versions
- 7. Start the Knox service
- 8. Test the SSO functionality to confirm the URL redirection vulnerability is resolved
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Knox
Scoped from the published advisory
- Consultation2.0 h
- Implementation2.0 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 $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-42357 — 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-2021-42357 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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