{"id":"CVE-2026-34950","summary":"fast-jwt has an incomplete fix for CVE-2023-48223: JWT Algorithm Confusion via Whitespace-Prefixed RSA Public Key","details":"fast-jwt provides fast JSON Web Token (JWT) implementation. In 6.1.0 and earlier, the publicKeyPemMatcher regex in fast-jwt/src/crypto.js uses a ^ anchor that is defeated by any leading whitespace in the key string, re-enabling the exact same JWT algorithm confusion attack that CVE-2023-48223 patched.","aliases":["GHSA-mvf2-f6gm-w987"],"modified":"2026-08-12T03:51:43.516725548Z","published":"2026-04-06T15:54:03.765Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34950.json","cna_assigner":"GitHub_M","cwe_ids":["CWE-327"]},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/34xxx/CVE-2026-34950.json"},{"type":"ADVISORY","url":"https://github.com/nearform/fast-jwt/security/advisories/GHSA-mvf2-f6gm-w987"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34950"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/nearform/fast-jwt","events":[{"introduced":"0"},{"fixed":"e07b1fd23f02a47f1be677a21a4f07607b478e66"}],"database_specific":{"source":["AFFECTED_FIELD","CPE_RANGE"],"cpe":"cpe:2.3:a:nearform:fast-jwt:*:*:*:*:*:node.js:*:*","extracted_events":[{"introduced":"0"},{"last_affected":"6.1.0"},{"fixed":"6.2.0"}]}}],"versions":["v6.1.0","v2.0.0","v1.7.2","v1.7.1","v1.7.0","v1.6.1","v1.6.0","v1.5.4","v1.5.3","v1.5.2","v1.5.1","v1.5.0","v1.4.1","v1.4.0","v1.3.2","v1.3.0","v1.2.0","v1.1.3","v1.1.2","v1.1.1","v1.1.0","v1.0.0","v0.5.1","v0.5.0","v0.4.2","v0.4.1","v0.4.0","v0.3.1","v0.3.0","v0.2.0","v0.1.1","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-34950.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N"}]}