{"affected":[{"defaultStatus":"unaffected","ecosystem":"pypi","packageName":"python-jose","product":"python-jose","source":"CNA: VulnCheck","vendor":"mpdavis","versions":[{"lessThanOrEqual":"3.5.0","status":"affected","version":"0","versionType":"semver"}]}],"cveId":"CVE-2026-120459","cwes":["CWE-347"],"description":"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.","epss":null,"exploits":[],"kev":null,"metrics":[{"score":9.1,"severity":"critical","source":"CNA: VulnCheck","vector":"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","version":"4.0"},{"score":7.4,"severity":"high","source":"CNA: VulnCheck","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"}],"modifiedAt":1793629755767,"publishedAt":1793629755767,"references":[{"source":"CNA: VulnCheck","tags":["issue-tracking"],"url":"https://github.com/mpdavis/python-jose/issues/398"},{"source":"CNA: VulnCheck","tags":["technical-description"],"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/native.py"},{"source":"CNA: VulnCheck","tags":["technical-description"],"url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py"},{"source":"CNA: VulnCheck","tags":["third-party-advisory"],"url":"https://www.vulncheck.com/advisories/python-jose-through-3.5.0-authentication-bypass-via-empty-hmac-key"}],"remediation":[],"revision":"91f4fb5cd0be342061061f9b4fb8e80065fb7e8ac120cd3398fc6d1f633177f2","sources":[{"modifiedAt":1793629755767,"name":"CNA: VulnCheck","retrievedAt":1793632136725,"url":"https://www.cve.org/CVERecord?id=CVE-2026-120459"}],"ssvc":null,"status":"published","title":"python-jose through 3.5.0 Authentication Bypass via Empty HMAC Key","updatedAt":1793632136725}