{"id":"UBUNTU-CVE-2026-120459","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":"2026-11-04T03:30:03.801534280Z","published":"2026-11-03T00:00:00Z","upstream":["CVE-2026-120459"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-120459"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-120459"},{"type":"REPORT","url":"https://github.com/mpdavis/python-jose/blob/3.5.0/jose/backends/cryptography_backend.py"},{"type":"REPORT","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":"REPORT","url":"https://www.vulncheck.com/advisories/python-jose-through-3.5.0-authentication-bypass-via-empty-hmac-key"}],"affected":[{"package":{"name":"python-jose","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/python-jose?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.3.0+dfsg-1"],"ecosystem_specific":{"binaries":[{"binary_version":"3.3.0+dfsg-1","binary_name":"python3-jose"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-120459.json"}},{"package":{"name":"python-jose","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/python-jose?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.3.0+dfsg-4"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-jose","binary_version":"3.3.0+dfsg-4"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-120459.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N"},{"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"},{"type":"Ubuntu","score":"medium"}]}