CVE-2026-42280
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 · uneditedAuth0.js is a client-side JavaScript library for Auth0. From 8.11.0 to 9.32.0, under specific preconditions, the Auth0.js SDK may improperly return user profile information using a valid access token when a specifically crafted invalid ID token is provided. This vulnerability is fixed in 10.0.0.
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 confidenceAuth0.js versions 8.11.0 through 9.32.0 contain an authentication bypass where, under specific preconditions involving a crafted invalid ID token used alongside a valid access token, the library improperly returns user profile information. This could enable unauthorized disclosure of user data.
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>= 8.11.0, < 10.0.0CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/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 Auth0.js installationSearch for 'auth0-js' or '@auth0/auth0-js' in package.json files, or look for the auth0.js script inclusion in HTML/JS filesAffected if Auth0.js is present in the project dependencies or loaded in the application
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Check installed versionRun 'npm list auth0-js' or 'npm list @auth0/auth0-js', or inspect the package.json version field, or check the version string in the loaded auth0.js scriptAffected if The version is >= 8.11.0 and < 10.0.0
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Verify authentication flow uses ID tokensReview the application code that calls Auth0.js methods such as 'parseHash', 'verifyToken', or 'client.userInfo(accessToken, idToken)' to see if both ID tokens and access tokens are processed togetherAffected if The application processes both an ID token and access token in the same authentication flow
You are affected if Auth0.js version is between 8.11.0 and 9.32.0 AND your application uses the authentication flow where a crafted invalid ID token could be supplied alongside a valid access token to trigger unauthorized profile data return.
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 · scoped10.0.0
Upgrade Auth0.js to version 10.0.0 or later to remediate this vulnerability.
10.0.0
- Upgrade Auth0.js to version 10.0.0 or later
- Update the package.json dependency to specify auth0-js@^10.0.0 or the latest available version
- Run npm install or yarn install to update the dependency
- Test the application to ensure authentication flows still work correctly after the upgrade
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-42280 — 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-2026-42280 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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