{"id":"GHSA-6g6m-m6h5-w9gf","summary":"Authorization bypass in express-jwt","details":"### Overview\nVersions before and including 5.3.3, we are not enforcing the **algorithms** entry to be specified in the configuration.\nWhen **algorithms** is not specified in the configuration, with the combination of jwks-rsa, it may lead to authorization bypass. \n\n### Am I affected?\nYou are affected by this vulnerability if all of the following conditions apply:\n\nYou are using express-jwt\nAND \nYou do not have **algorithms**  configured in your express-jwt configuration.\nAND\nYou are using libraries such as jwks-rsa as the **secret**. \n\n### How to fix that?\nSpecify **algorithms** in the express-jwt configuration. The following is an example of a proper configuration\n\n``` \nconst checkJwt = jwt({\n  secret: jwksRsa.expressJwtSecret({\n    rateLimit: true,\n    jwksRequestsPerMinute: 5,\n    jwksUri: `https://${DOMAIN}/.well-known/jwks.json`\n  }),\n  // Validate the audience and the issuer.\n  audience: process.env.AUDIENCE,\n  issuer: `https://${DOMAIN}/`,\n  // restrict allowed algorithms\n  algorithms: ['RS256']\n}); \n```\n\n### Will this update impact my users?\nThe fix provided in patch will not affect your users if you specified the algorithms allowed. The patch now makes **algorithms** a required configuration. \n\n\n### Credit\nIST Group","aliases":["CVE-2020-15084"],"modified":"2026-07-08T06:28:48.938804748Z","published":"2020-06-30T16:05:24Z","database_specific":{"github_reviewed":true,"github_reviewed_at":"2020-06-30T16:04:48Z","nvd_published_at":"2020-06-30T16:15:00Z","cwe_ids":["CWE-285","CWE-863"],"severity":"HIGH"},"references":[{"type":"WEB","url":"https://github.com/auth0/express-jwt/security/advisories/GHSA-6g6m-m6h5-w9gf"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2020-15084"},{"type":"WEB","url":"https://github.com/auth0/express-jwt/commit/7ecab5f8f0cab5297c2b863596566eb0c019cdef"}],"affected":[{"package":{"name":"express-jwt","ecosystem":"npm","purl":"pkg:npm/express-jwt"},"ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"6.0.0"}]}],"database_specific":{"last_known_affected_version_range":"\u003c= 5.3.3","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2020/06/GHSA-6g6m-m6h5-w9gf/GHSA-6g6m-m6h5-w9gf.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:N"}]}