{"id":"CVE-2026-120459","title":"python-jose through 3.5.0 Authentication Bypass via Empty HMAC Key","summary":"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/HS51…","severity":"high","cvss":7.4,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","cvssSource":"cna","cwe":["CWE-347"],"vendor":"mpdavis","product":"python-jose","affected":["python-jose <= 3.5.0"],"published":"2026-11-02","updated":"2026-11-02","sourceUpdated":"2026-11-02T14:29:15.767Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-120459","references":[{"url":"https://github.com/mpdavis/python-jose/issues/398"},{"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/native.py"},{"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py"},{"url":"https://www.vulncheck.com/advisories/python-jose-through-3.5.0-authentication-bypass-via-empty-hmac-key","label":"VulnCheck Advisory: python-jose through 3.5.0 Authentication Bypass via Empty HMAC Key"}],"tags":["cve.org"],"epss":0.00251,"epssPercentile":0.16568,"ingestedAt":"2026-11-05T19:30:42.662Z","slug":"CVE-2026-120459","body":"## Overview\n\npython-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.\n\n## Affected\n\n- `python-jose <= 3.5.0`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":41,"depthScoreParts":{"impact":40.7,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}