{"id":"CVE-2026-81853","state":"PUBLISHED","title":"AshAdmin composite primary key decoding accepts arbitrary fields, enabling a secret-attribute oracle","description":"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.","publishedAt":"2026-08-31T02:31:29.547Z","updatedAt":"2026-08-31T15:58:40.226Z","severity":{"score":2.3,"label":"Low","version":"4.0","vector":"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","source":"EEF"},"assigner":"EEF","products":["ash-project ash_admin"],"affected":[{"vendor":"ash-project","product":"ash_admin","packageName":"ash_admin","packageURL":"pkg:hex/ash_admin","defaultStatus":"unaffected","versions":[{"version":"0.1.0","status":"affected","lessThan":"1.3.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAdmin.Helpers'"],"programFiles":["lib/ash_admin/helpers.ex"],"programRoutines":[{"name":"'Elixir.AshAdmin.Helpers':decode_primary_key/2"}],"repo":"https://github.com/ash-project/ash_admin"},{"vendor":"ash-project","product":"ash_admin","packageName":"ash-project/ash_admin","packageURL":"pkg:github/ash-project/ash_admin","defaultStatus":"unaffected","versions":[{"version":"98b03baa8422b94dd13e305bf08b8ee3f7232c7b","status":"affected","lessThan":"3c3e905d47f1155dcc1ca3fb347348b05a66065a","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAdmin.Helpers'"],"programFiles":["lib/ash_admin/helpers.ex"],"programRoutines":[{"name":"'Elixir.AshAdmin.Helpers':decode_primary_key/2"}],"repo":"https://github.com/ash-project/ash_admin"}],"references":["https://github.com/ash-project/ash_admin/security/advisories/GHSA-jxr8-hpv2-qp38","https://cna.erlef.org/cves/CVE-2026-81853.html","https://osv.dev/vulnerability/EEF-CVE-2026-81853","https://github.com/ash-project/ash_admin/commit/3c3e905d47f1155dcc1ca3fb347348b05a66065a"],"weaknesses":["CWE-639"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/81xxx/CVE-2026-81853.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81853","state":"PUBLISHED","datePublished":"2026-08-31T02:31:29.547Z","dateUpdated":"2026-08-31T15:58:40.226Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-08-30T23:15:02.371Z"},"containers":{"cna":{"title":"AshAdmin composite primary key decoding accepts arbitrary fields, enabling a secret-attribute oracle","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"ash-project","product":"ash_admin","packageName":"ash_admin","packageURL":"pkg:hex/ash_admin","defaultStatus":"unaffected","versions":[{"version":"0.1.0","status":"affected","lessThan":"1.3.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAdmin.Helpers'"],"programFiles":["lib/ash_admin/helpers.ex"],"programRoutines":[{"name":"'Elixir.AshAdmin.Helpers':decode_primary_key/2"}],"repo":"https://github.com/ash-project/ash_admin"},{"vendor":"ash-project","product":"ash_admin","packageName":"ash-project/ash_admin","packageURL":"pkg:github/ash-project/ash_admin","defaultStatus":"unaffected","versions":[{"version":"98b03baa8422b94dd13e305bf08b8ee3f7232c7b","status":"affected","lessThan":"3c3e905d47f1155dcc1ca3fb347348b05a66065a","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAdmin.Helpers'"],"programFiles":["lib/ash_admin/helpers.ex"],"programRoutines":[{"name":"'Elixir.AshAdmin.Helpers':decode_primary_key/2"}],"repo":"https://github.com/ash-project/ash_admin"}],"references":[{"url":"https://github.com/ash-project/ash_admin/security/advisories/GHSA-jxr8-hpv2-qp38","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-81853.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-81853","tags":["related"]},{"url":"https://github.com/ash-project/ash_admin/commit/3c3e905d47f1155dcc1ca3fb347348b05a66065a","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":2.3,"baseSeverity":"LOW","privilegesRequired":"LOW","providerUrgency":"NOT_DEFINED","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","valueDensity":"NOT_DEFINED","vectorString":"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","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"LOW","vulnIntegrityImpact":"NONE","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-639","description":"CWE-639 Authorization Bypass Through User-Controlled Key","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-08-31T02:31:29.547Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>The resource has a composite primary key, and the deployment relies on AshAdmin's authorization (a custom actor plug and policies) so that reading otherwise-restricted attribute values crosses a boundary.</p>"},{"base64":false,"type":"text/markdown","value":"The resource has a composite primary key, and the deployment relies on AshAdmin's authorization (a custom actor plug and policies) so that reading otherwise-restricted attribute values crosses a boundary."}],"value":"The resource has a composite primary key, and the deployment relies on AshAdmin's authorization (a custom actor plug and policies) so that reading otherwise-restricted attribute values crosses a boundary."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:ash-project:ash_admin:*:*:*:*:*:*:*:*","versionEndExcluding":"1.3.1","versionStartIncluding":"0.1.0","vulnerable":true}],"negate":false,"operator":"OR"}],"operator":"AND"}],"credits":[{"lang":"en","type":"finder","value":"Peter Ullrich"},{"lang":"en","type":"reporter","value":"Peter Ullrich"},{"lang":"en","type":"remediation developer","value":"Zach Daniel / Ash Project"},{"lang":"en","type":"coordinator","value":"Jonatan Männchen / EEF"}],"impacts":[{"capecId":"CAPEC-77","descriptions":[{"lang":"en","value":"CAPEC-77 Manipulating User-Controlled Variables"}]}],"source":{"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","references":[{"url":"https://github.com/ash-project/ash_admin/security/advisories/GHSA-jxr8-hpv2-qp38","tags":["exploit"]}],"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-08-31T15:57:41.689629Z","id":"CVE-2026-81853","options":[{"Exploitation":"poc"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-08-31T15:58:40.226Z"}}]}}}