{"id":"CVE-2026-82754","summary":"ash_authentication_oauth2_server aliases every protocol endpoint under /.well-known, bypassing path-scoped controls","details":"Improper Protection of Alternate Path vulnerability in ash-project ash_authentication_oauth2_server exposes the state-changing OAuth endpoints under an unintended URL prefix, bypassing controls scoped to the canonical prefix.\n\noauth2_server_protocol_routes/1 in AshAuthentication.Phoenix.Oauth2Server.Router forwards the same ProtocolRouter at both the /oauth prefix and the /.well-known prefix. Phoenix forward strips the matched prefix before dispatch, so the full route table answers under both mounts, and POST /register, POST /token, and POST /revoke are reachable as /.well-known/register, /.well-known/token, and /.well-known/revoke. Edge controls such as WAF rules, rate limits, or authentication exemptions written against the /oauth paths, or that allow-list /.well-known as unauthenticated, do not apply to the alias.\n\nThis issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.","aliases":["EEF-CVE-2026-82754","GHSA-wwxg-h779-3wf4"],"modified":"2026-09-09T03:47:29.340741113Z","published":"2026-09-07T22:23:56.762Z","database_specific":{"cwe_ids":["CWE-424"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82754.json","unresolved_ranges":[{"extracted_events":[{"introduced":"855b578037c5ded18e8a6e60f42e56bde4905fae"},{"fixed":"a72972d7ed3eb74c05dfa0653a258ef14454459a"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"EEF"},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-82754.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-82754"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82754.json"},{"type":"ADVISORY","url":"https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-wwxg-h779-3wf4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-82754"},{"type":"FIX","url":"https://github.com/ash-project/ash_authentication_oauth2_server/commit/a72972d7ed3eb74c05dfa0653a258ef14454459a"},{"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":"a72972d7ed3eb74c05dfa0653a258ef14454459a"}],"database_specific":{"extracted_events":[{"introduced":"0.1.0"},{"fixed":"0.3.1"}],"source":["DESCRIPTION","REFERENCES"]}}],"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-2026-82754.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"}]}