{"id":"UBUNTU-CVE-2026-114620","details":"Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to 1.9.0, Authlib's RFC 9101 JWTAuthenticationRequest passes the unauthenticated, client-controlled request_uri parameter to the abstract get_request_object() hook before applying a destination or registration policy; the hook itself performs no network request, while the documentation demonstrates an unrestricted HTTP fetch. In deployments whose integrator implements that hook as an unrestricted outbound fetch, a remote attacker who knows a valid public client identifier can make the authorization server request internal, link-local, or otherwise unintended URLs and can distinguish fetch outcomes through different error responses and timing. Deployments whose custom hook already applies a secure allowlist, destination controls, and retrieval limits are not affected. The JWTAuthenticationRequest implementation in authlib/oauth2/rfc9101/authorization_server.py forwards request_uri to get_request_object() before an application-approved retrieval policy accepts the destination. This issue is fixed in version 1.9.0.","modified":"2026-10-28T17:50:37Z","published":"2026-10-22T22:18:00Z","upstream":["CVE-2026-114620"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-114620"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-114620"},{"type":"REPORT","url":"https://github.com/authlib/authlib/commit/6563f6f7a8c2f71d2f85ee7511d72a4fbae3acc0"},{"type":"REPORT","url":"https://github.com/authlib/authlib/commit/891e3f10ae5989176211f8be35dcc7cd40aa92c6"},{"type":"REPORT","url":"https://github.com/authlib/authlib/pull/949"},{"type":"REPORT","url":"https://github.com/authlib/authlib/releases/tag/v1.9.0"},{"type":"REPORT","url":"https://github.com/authlib/authlib/security/advisories/GHSA-x4rv-c3wx-4cr8"}],"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-2026-114620.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-2026-114620.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-2026-114620.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-2026-114620.json"}}],"schema_version":"1.9.2","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}