{"id":"CVE-2026-82758","state":"PUBLISHED","title":"ash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpoint","description":"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.","publishedAt":"2026-09-07T22:32:17.027Z","updatedAt":"2026-09-08T14:41:06.227Z","severity":{"score":6.3,"label":"Medium","version":"4.0","vector":"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","source":"EEF"},"assigner":"EEF","products":["ash-project ash_authentication_oauth2_server"],"affected":[{"vendor":"ash-project","product":"ash_authentication_oauth2_server","packageName":"ash_authentication_oauth2_server","packageURL":"pkg:hex/ash_authentication_oauth2_server","defaultStatus":"unaffected","versions":[{"version":"0.1.0","status":"affected","lessThan":"0.3.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.Oauth2Server'"],"programFiles":["lib/ash_authentication/oauth2_server.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.Oauth2Server':__resolve_secret__!/3"}],"repo":"https://github.com/ash-project/ash_authentication_oauth2_server"},{"vendor":"ash-project","product":"ash_authentication_oauth2_server","packageName":"ash-project/ash_authentication_oauth2_server","packageURL":"pkg:github/ash-project/ash_authentication_oauth2_server","defaultStatus":"unaffected","versions":[{"version":"855b578037c5ded18e8a6e60f42e56bde4905fae","status":"affected","lessThan":"30a87101871775d27d79f9ad6f29eafa4779e118","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.Oauth2Server'"],"programFiles":["lib/ash_authentication/oauth2_server.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.Oauth2Server':__resolve_secret__!/3"}],"repo":"https://github.com/ash-project/ash_authentication_oauth2_server"}],"references":["https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw","https://cna.erlef.org/cves/CVE-2026-82758.html","https://osv.dev/vulnerability/EEF-CVE-2026-82758","https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118"],"weaknesses":["CWE-287"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/82xxx/CVE-2026-82758.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-82758","state":"PUBLISHED","datePublished":"2026-09-07T22:32:17.027Z","dateUpdated":"2026-09-08T14:41:06.227Z","assignerShortName":"EEF","assignerOrgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateReserved":"2026-08-31T01:00:10.817Z"},"containers":{"cna":{"title":"ash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpoint","descriptions":[{"lang":"en","value":"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."}],"affected":[{"vendor":"ash-project","product":"ash_authentication_oauth2_server","packageName":"ash_authentication_oauth2_server","packageURL":"pkg:hex/ash_authentication_oauth2_server","defaultStatus":"unaffected","versions":[{"version":"0.1.0","status":"affected","lessThan":"0.3.1","versionType":"semver"}],"collectionURL":"https://repo.hex.pm","cpes":["cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.Oauth2Server'"],"programFiles":["lib/ash_authentication/oauth2_server.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.Oauth2Server':__resolve_secret__!/3"}],"repo":"https://github.com/ash-project/ash_authentication_oauth2_server"},{"vendor":"ash-project","product":"ash_authentication_oauth2_server","packageName":"ash-project/ash_authentication_oauth2_server","packageURL":"pkg:github/ash-project/ash_authentication_oauth2_server","defaultStatus":"unaffected","versions":[{"version":"855b578037c5ded18e8a6e60f42e56bde4905fae","status":"affected","lessThan":"30a87101871775d27d79f9ad6f29eafa4779e118","versionType":"git"}],"collectionURL":"https://github.com","cpes":["cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"],"modules":["'Elixir.AshAuthentication.Oauth2Server'"],"programFiles":["lib/ash_authentication/oauth2_server.ex"],"programRoutines":[{"name":"'Elixir.AshAuthentication.Oauth2Server':__resolve_secret__!/3"}],"repo":"https://github.com/ash-project/ash_authentication_oauth2_server"}],"references":[{"url":"https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw","tags":["vendor-advisory","related"]},{"url":"https://cna.erlef.org/cves/CVE-2026-82758.html","tags":["related"]},{"url":"https://osv.dev/vulnerability/EEF-CVE-2026-82758","tags":["related"]},{"url":"https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118","tags":["patch"]}],"metrics":[{"cvssV4_0":{"Automatable":"NOT_DEFINED","Recovery":"NOT_DEFINED","Safety":"NOT_DEFINED","attackComplexity":"LOW","attackRequirements":"PRESENT","attackVector":"NETWORK","baseScore":6.3,"baseSeverity":"MEDIUM","privilegesRequired":"NONE","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:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"NONE","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"LOW","vulnerabilityResponseEffort":"NOT_DEFINED"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"problemTypes":[{"descriptions":[{"cweId":"CWE-287","description":"CWE-287 Improper Authentication","lang":"en","type":"CWE"}]}],"providerMetadata":{"shortName":"EEF","orgId":"6b3ad84c-e1a6-4bf7-a703-f496b71e49db","dateUpdated":"2026-09-07T22:32:17.027Z"},"configurations":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"<p>Reachable only when the server configures an <code>initial_access_token</code> (so Dynamic Client Registration is meant to require one) and the configured secret provider returns an empty value (<code>nil</code>, <code>false</code>, or <code>\"\"</code>) or an <code>{:error, _}</code> for it, rather than a non-empty binary.</p>"},{"base64":false,"type":"text/markdown","value":"Reachable only when the server configures an `initial_access_token` (so Dynamic Client Registration is meant to require one) and the configured secret provider returns an empty value (`nil`, `false`, or `\"\"`) or an `{:error, _}` for it, rather than a non-empty binary."}],"value":"Reachable only when the server configures an initial_access_token (so Dynamic Client Registration is meant to require one) and the configured secret provider returns an empty value (nil, false, or \"\") or an {:error, _} for it, rather than a non-empty binary."}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*","versionEndExcluding":"0.3.1","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-115","descriptions":[{"lang":"en","value":"CAPEC-115 Authentication Bypass"}]}],"source":{"discovery":"EXTERNAL"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-08T14:40:53.437993Z","id":"CVE-2026-82758","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-08T14:41:06.227Z"}}]}}}