{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-82758", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-08-31T01:00:10.817Z", "datePublished": "2026-09-07T22:32:17.027Z", "dateUpdated": "2026-09-07T22:32:17.027Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.AshAuthentication.Oauth2Server'"], "packageName": "ash_authentication_oauth2_server", "packageURL": "pkg:hex/ash_authentication_oauth2_server", "product": "ash_authentication_oauth2_server", "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", "versions": [{"lessThan": "0.3.1", "status": "affected", "version": "0.1.0", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.AshAuthentication.Oauth2Server'"], "packageName": "ash-project/ash_authentication_oauth2_server", "packageURL": "pkg:github/ash-project/ash_authentication_oauth2_server", "product": "ash_authentication_oauth2_server", "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", "versions": [{"lessThan": "30a87101871775d27d79f9ad6f29eafa4779e118", "status": "affected", "version": "855b578037c5ded18e8a6e60f42e56bde4905fae", "versionType": "git"}]}], "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 M\u00e4nnchen / EEF"}], "descriptions": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>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.</p>\n<p><code>resolve_secret/3</code> in <code>AshAuthentication.Oauth2Server</code> (reached through <code>__resolve_secret__!</code>) treated any return other than <code>{:ok, _}</code> or <code>:error</code> from a configured <code>{module, function, args}</code> or 2-arity-function secret provider as a valid secret, wrapping <code>nil</code>, <code>false</code>, or <code>\"\"</code> as <code>{:ok, value}</code>. When the <code>initial_access_token</code> resolves to such an empty value, <code>POST /oauth/register</code> 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 <code>signing_secret</code>.</p>\n<p>This issue affects ash_authentication_oauth2_server: from 0.1.0 before 0.3.1.</p>"}, {"base64": false, "type": "text/markdown", "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\n`resolve_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."}], "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."}], "impacts": [{"capecId": "CAPEC-115", "descriptions": [{"lang": "en", "value": "CAPEC-115 Authentication Bypass"}]}], "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": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-09-07T22:32:17.027Z"}, "references": [{"tags": ["vendor-advisory", "related"], "url": "https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-fxc6-vp68-87pw"}, {"tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-82758.html"}, {"tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82758"}, {"tags": ["patch"], "url": "https://github.com/ash-project/ash_authentication_oauth2_server/commit/30a87101871775d27d79f9ad6f29eafa4779e118"}], "source": {"discovery": "EXTERNAL"}, "title": "ash_authentication_oauth2_server treats an empty resolved secret as valid, opening the gated Dynamic Client Registration endpoint"}}}

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