{"id":"UBUNTU-CVE-2026-28490","details":"Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a cryptographic padding oracle vulnerability was identified in the Authlib Python library concerning the implementation of the JSON Web Encryption (JWE) RSA1_5 key management algorithm. Authlib registers RSA1_5 in its default algorithm registry without requiring explicit opt-in, and actively destroys the constant-time Bleichenbacher mitigation that the underlying cryptography library implements correctly. This issue has been patched in version 1.6.9.","modified":"2026-07-17T01:21:44.958562716Z","published":"2026-03-16T18:16:00Z","related":["USN-8557-1"],"upstream":["CVE-2026-28490"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-28490"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-28490"},{"type":"REPORT","url":"https://github.com/authlib/authlib/security/advisories/GHSA-7432-952r-cw78"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8557-1"}],"affected":[{"package":{"name":"python-authlib","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/python-authlib?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.15.5-1ubuntu0.1~esm2"}]}],"versions":["0.15.4-1","0.15.5-1","0.15.5-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-authlib","binary_version":"0.15.5-1ubuntu0.1~esm2"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28490.json"}},{"package":{"name":"python-authlib","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/python-authlib?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.3.0-1ubuntu0.1~esm2"}]}],"versions":["1.2.1-1","1.3.0-1","1.3.0-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-authlib","binary_version":"1.3.0-1ubuntu0.1~esm2"}],"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28490.json"}},{"package":{"name":"python-authlib","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/python-authlib?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.1-1","1.5.2-1","1.6.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-authlib","binary_version":"1.6.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28490.json"}},{"package":{"name":"python-authlib","ecosystem":"Ubuntu:Pro:26.04:LTS","purl":"pkg:deb/ubuntu/python-authlib?arch=source&distro=esm-apps%2Fresolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.7-1ubuntu0.1~esm1"}]}],"versions":["1.6.0-1","1.6.5-1","1.6.6-1","1.6.7-1"],"ecosystem_specific":{"availability":"Available with Ubuntu Pro: https://ubuntu.com/pro","binaries":[{"binary_name":"python3-authlib","binary_version":"1.6.7-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-28490.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}