{"id":"CVE-2026-82758","summary":"ash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpoint","details":"Improper Authentication vulnerability in ash-project ash_authentication_oauth2_server allows an unauthenticated attacker to register OAuth clients even when Dynamic Client Registration is gated by an initial access token.\n\nresolve_secret/3 in AshAuthentication.Oauth2Server (reached through __resolve_secret__!) treated any return other than {:ok, _} or :error from a configured {module, function, args} or 2-arity-function secret provider as a valid secret, wrapping nil, false, or \"\" as {:ok, value}. When the initial_access_token resolves to such an empty value, POST /oauth/register compares the presented bearer token against it and the comparison passes with no token supplied, so registration is open although it was configured closed. The same fail-open affected other resolved secrets such as signing_secret.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.","aliases":["EEF-CVE-2026-82758","GHSA-fxc6-vp68-87pw"],"modified":"2026-09-10T03:30:39.989668877Z","published":"2026-09-07T22:32:17.027Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82758.json","unresolved_ranges":[{"extracted_events":[{"introduced":"855b578037c5ded18e8a6e60f42e56bde4905fae"},{"fixed":"30a87101871775d27d79f9ad6f29eafa4779e118"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"EEF","cwe_ids":["CWE-287"]},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-82758.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-82758"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82758.json"},{"type":"ADVISORY","url":"https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-82758"},{"type":"FIX","url":"https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118"},{"type":"PACKAGE","url":"https://github.com/ash-project/ash_authentication_oauth2_server"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ash-project/ash_authentication_oauth2_server","events":[{"introduced":"a4d8c361f710e5a050a1cf4834c9fa6c8f3dbd01"},{"fixed":"15bde4311e31c925a428f34c02b283307619e2a2"},{"fixed":"30a87101871775d27d79f9ad6f29eafa4779e118"}],"database_specific":{"source":["DESCRIPTION","REFERENCES"],"extracted_events":[{"introduced":"0.1.0"},{"fixed":"0.3.1"}]}}],"versions":["v0.3.0","v0.2.2","v0.2.1","v0.2.0","v0.1.3","v0.1.2","v0.1.1","v0.1.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-82758.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N"}]}