{"id":"CVE-2026-116672","published":"2026-10-27T17:16:59.140","lastModified":"2026-10-27T21:31:20.100","description":"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.","cvssScore":8.8,"cvssSeverity":"HIGH","cvssVector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","cwes":["CWE-639","CWE-1188"],"vendors":[],"products":[],"references":[{"url":"https://github.com/authlib/authlib/commit/1bd2a313492ce0a4d0571c150730907aa3fc91ff","tags":[]},{"url":"https://github.com/authlib/authlib/releases/tag/v1.9.1","tags":[]},{"url":"https://github.com/authlib/authlib/security/advisories/GHSA-c73q-w75p-j82v","tags":[]}],"exploitRefs":[{"url":"https://github.com/authlib/authlib/commit/1bd2a313492ce0a4d0571c150730907aa3fc91ff","tags":[]},{"url":"https://github.com/authlib/authlib/releases/tag/v1.9.1","tags":[]},{"url":"https://github.com/authlib/authlib/security/advisories/GHSA-c73q-w75p-j82v","tags":[]}],"hasPoc":true,"ai":null}