Express JwtApplication · Auth0

CVE-2020-15084

CRITICAL · 9.1 CVSS v3.1 Published 2020-06-30
Fix available
A fix is available. Upgrade to after 5.3.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

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 · unedited
In express-jwt (NPM package) up and including version 5.3.3, the algorithms entry to be specified in the configuration is not being enforced. When algorithms is not specified in the configuration, with the combination of jwks-rsa, it may lead to authorization bypass. You are affected by this vulnerability if all of the following conditions apply: - You are using express-jwt - You do not have **algorithms** configured in your express-jwt configuration. - You are using libraries such as jwks-rsa as the **secret**. You can fix this by specifying **algorithms** in the express-jwt configuration. See linked GHSA for example. This is also fixed in version 6.0.0.

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
How this class of weakness works · CWE-285

The application confirms who you are but does not properly check whether you are permitted to perform a given action, so authenticated users reach functions or data meant for others. Attackers test roles and object references to find the gap. Remediation is an authorization check on every request, evaluated against the acting user's actual permissions.

General guidance for the improper authorization class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

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
Express JwtApplication
Affected:<= 5.3.3

CVSS 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
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

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 · scoped
Upgrade available Upgrade to a release after 5.3.3
Vendor patch github.com →
Recommended fix High confidence

6.0.0 or later

  1. 1. Review your project's package.json to identify express-jwt dependency version
  2. 2. Update express-jwt to version 6.0.0 or later by running: npm install express-jwt@^6.0.0
  3. 3. Test your application thoroughly after the upgrade to ensure authentication and authorization work correctly
  4. 4. Alternatively, if upgrading is not immediately feasible, add the algorithms option to your express-jwt configuration (e.g., algorithms: ['HS256'] or algorithms: ['RS256'] for jwks-rsa)
Caveat Review the express-jwt v6.0.0 release notes for any breaking changes before upgrading

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2020-15084 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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