{"id":"UBUNTU-CVE-2026-116672","details":"Authlib is a Python library which builds OAuth and OpenID Connect servers. From 0.15 until 1.9.1, the documented ClientConfigurationEndpoint.authenticate_client and ClientConfigurationEndpoint.check_permission reference implementations look up a target client from request-controlled client_id data and check only whether that target is editable, without verifying that request.credential belongs to the target client. Deployments following both examples can allow a client holding any valid registration access token to read, modify, or delete another client's registration. Changing redirect_uris can enable authorization code or token interception, while deleting registrations can deny service to affected clients. This issue is fixed in version 1.9.1.","modified":"2026-10-28T20:17:45.748854033Z","published":"2026-10-27T17:16:00Z","upstream":["CVE-2026-116672"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-116672"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-116672"},{"type":"REPORT","url":"https://github.com/authlib/authlib/security/advisories/GHSA-c73q-w75p-j82v"},{"type":"REPORT","url":"https://github.com/authlib/authlib/commit/1bd2a313492ce0a4d0571c150730907aa3fc91ff"},{"type":"REPORT","url":"https://github.com/authlib/authlib/releases/tag/v1.9.1"}],"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"}]}],"versions":["0.15.4-1","0.15.5-1","0.15.5-1ubuntu0.1~esm1","0.15.5-1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-authlib","binary_version":"0.15.5-1ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-116672.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"}]}],"versions":["1.2.1-1","1.3.0-1","1.3.0-1ubuntu0.1~esm1","1.3.0-1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"1.3.0-1ubuntu0.1~esm2","binary_name":"python3-authlib"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-116672.json"}},{"package":{"name":"python-authlib","ecosystem":"Ubuntu:26.10","purl":"pkg:deb/ubuntu/python-authlib?arch=source&distro=stonking"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.6.7-1","1.7.2-1","1.7.2-2"],"ecosystem_specific":{"binaries":[{"binary_name":"python3-authlib","binary_version":"1.7.2-2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-116672.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"}]}],"versions":["1.6.0-1","1.6.5-1","1.6.6-1","1.6.7-1","1.6.7-1ubuntu0.1~esm1"],"ecosystem_specific":{"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-2026-116672.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]}