{"id":"CVE-2026-81853","summary":"AshAdmin composite primary key decoding accepts arbitrary fields, enabling a secret-attribute oracle","details":"Authorization Bypass Through User-Controlled Key vulnerability in ash-project ash_admin turns a record-lookup URL into an equality oracle over sensitive attributes.\n\nAshAdmin.Helpers.decode_primary_key/2 decodes the composite-primary-key form (Base64 plus ETF) and returns the decoded map verbatim as the lookup filter, without checking that its keys are the resource's primary-key fields. The deserialization guards bound size, block new atoms and funs, and reject nested expressions, but none restricts which fields come back, and :safe still allows any already-interned attribute name. An attacker can therefore encode %{api_token: \"guess\"} and have it spliced into the lookup filter, brute-forcing a sensitive attribute value (API token, reset token) one equality guess at a time; Map.to_list/1 also accepts structs, yielding a bogus __struct__ key. The fix rejects any decoded key that is not a real primary-key field.\n\nThis issue affects ash_admin: from 0.1.0 before 1.3.1.","aliases":["EEF-CVE-2026-81853","GHSA-jxr8-hpv2-qp38"],"modified":"2026-09-03T03:30:23.424513130Z","published":"2026-08-31T02:31:29.547Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81853.json","unresolved_ranges":[{"extracted_events":[{"introduced":"98b03baa8422b94dd13e305bf08b8ee3f7232c7b"},{"fixed":"3c3e905d47f1155dcc1ca3fb347348b05a66065a"}],"source":"AFFECTED_FIELD"}],"cna_assigner":"EEF","cwe_ids":["CWE-639"]},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-81853.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-81853"},{"type":"WEB","url":"https://repo.hex.pm"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/81xxx/CVE-2026-81853.json"},{"type":"ADVISORY","url":"https://github.com/ash-project/ash_admin/security/advisories/GHSA-jxr8-hpv2-qp38"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-81853"},{"type":"FIX","url":"https://github.com/ash-project/ash_admin/commit/3c3e905d47f1155dcc1ca3fb347348b05a66065a"},{"type":"PACKAGE","url":"https://github.com/ash-project/ash_admin"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/ash-project/ash_admin","events":[{"introduced":"d99db5e821f4eebd45b96a4ed169f949d43b69d6"},{"fixed":"91da87c1c23cd6199ba1b0a1c8849a4c605130cc"},{"fixed":"3c3e905d47f1155dcc1ca3fb347348b05a66065a"}],"database_specific":{"source":["DESCRIPTION","REFERENCES"],"extracted_events":[{"introduced":"0.1.0"},{"fixed":"1.3.1"}]}}],"versions":["v1.3.0","v1.2.0","v1.1.0","v0.14.0","v0.13.26","v0.13.25","v0.13.24","v0.13.23","v0.13.22","v0.13.21","v0.13.20","v0.13.19","v0.13.18","v0.13.17","v0.13.16","v0.13.15","v0.13.14","v0.13.13","v0.13.12","v0.13.11","v0.13.10","v0.13.9","v0.13.8","v0.13.7","v0.13.6","v0.13.5","v0.13.4","v0.13.3","v0.13.2","v0.13.0","v0.12.6","v0.12.5","v0.12.4","v0.12.3","v0.12.2","v0.12.1","v0.12.0","v0.11.11","v0.11.10","v0.11.9","v0.11.8","v0.11.7","v0.11.6","v0.11.4","v0.11.3","v0.11.2","v0.11.1","v0.10.10","v0.10.10-rc.1","v0.10.10-rc.0","v0.10.9","v0.10.8","v0.10.7","v0.10.6","v0.10.5","v0.10.4","v0.10.3","v0.10.2","v0.10.1","v0.10.0","v0.9.8","v0.9.7","v0.9.6","v0.9.5","v0.9.4","v0.9.2","v0.9.1","v0.9.0","v0.8.2","v0.8.1","v0.8.0","v0.7.1","v0.7.0","v0.6.2","v0.6.1","v0.6.0-rc.2","v0.6.0-rc.1","v0.6.0-rc.0","v0.5.2","v0.5.1-rc.0","v0.5.0","v0.4.5-rc.0","v0.4.4","v0.4.3","v0.4.2","v0.4.1","v0.4.0","v0.3.0-rc.0","v0.2.22","v0.2.21","v0.2.20","v0.2.19","v0.2.18","v0.2.17","v0.2.16-rc.1","v0.2.16-rc.0","v0.2.15","v0.2.14","v0.2.13","v0.2.12","v0.2.11","v0.2.10","v0.2.9","v0.2.8","v0.2.7","v0.2.6","v0.2.5","v0.2.4","v0.2.3","v0.2.2","v0.2.1","v0.2.0","v0.1.6","v0.1.5","v0.1.4","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-2026-81853.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N"}]}