{"id":"CVE-2026-120459","summary":"python-jose through 3.5.0 Authentication Bypass via Empty HMAC Key","details":"python-jose through 3.5.0 contains an authentication bypass vulnerability that allows unauthenticated attackers to forge JWTs because HMACKey and CryptographyHMACKey accept zero-length HMAC secrets. When an application's HS256/HS384/HS512 verification key resolves to empty, such as an oct JWK with empty k, attackers can forge tokens with arbitrary claims that jwt.decode accepts.","modified":"2026-11-03T02:46:44.289636533Z","published":"2026-11-02T14:29:15.767Z","database_specific":{"cna_assigner":"VulnCheck","cwe_ids":["CWE-347"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/120xxx/CVE-2026-120459.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/120xxx/CVE-2026-120459.json"},{"type":"PACKAGE","url":"https://github.com/mpdavis/python-jose"},{"type":"ARTICLE","url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py"},{"type":"ARTICLE","url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/native.py"},{"type":"REPORT","url":"https://github.com/mpdavis/python-jose/issues/398"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-120459"},{"type":"ADVISORY","url":"https://www.vulncheck.com/advisories/python-jose-through-3.5.0-authentication-bypass-via-empty-hmac-key"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/mpdavis/python-jose","events":[{"introduced":"0"},{"last_affected":"018b310ddb8b50dcfd09a0c152117835a21dd656"}],"database_specific":{"extracted_events":[{"range":[{"introduced":"0"},{"last_affected":"3.5.0"}],"source":"AFFECTED_FIELD","strategy":"StandardRange"}]}}],"versions":["3.5.0","3.4.0","3.3.0","3.2.0","3.1.0","3.0.1","3.0.0","2.0.2","2.0.1","1.4.0","1.3.2","1.3.1","1.3.0","1.2.0","1.1.0","1.0.0","0.7.0","0.6.2","0.6.1","0.6.0","0.5.6","0.5.5","v0.5.4","0.5.3","v0.5.2","v0.5.1","v0.2.0","v0.1.5"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-120459.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N"}]}