{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-82757", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-08-31T01:00:10.817Z", "datePublished": "2026-09-07T22:31:34.656Z", "dateUpdated": "2026-09-07T22:31:34.656Z"}, "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.CIMD.ReqFetcher'"], "packageName": "ash_authentication_oauth2_server", "packageURL": "pkg:hex/ash_authentication_oauth2_server", "product": "ash_authentication_oauth2_server", "programFiles": ["lib/ash_authentication/oauth2_server/cimd/req_fetcher.ex"], "programRoutines": [{"name": "'Elixir.AshAuthentication.Oauth2Server.CIMD.ReqFetcher':public_ip?/1"}, {"name": "'Elixir.AshAuthentication.Oauth2Server.CIMD.ReqFetcher':fetch/2"}], "repo": "https://github.com/ash-project/ash_authentication_oauth2_server", "vendor": "ash-project", "versions": [{"lessThan": "0.3.1", "status": "affected", "version": "0.3.0", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.AshAuthentication.Oauth2Server.CIMD.ReqFetcher'"], "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/cimd/req_fetcher.ex"], "programRoutines": [{"name": "'Elixir.AshAuthentication.Oauth2Server.CIMD.ReqFetcher':public_ip?/1"}, {"name": "'Elixir.AshAuthentication.Oauth2Server.CIMD.ReqFetcher':fetch/2"}], "repo": "https://github.com/ash-project/ash_authentication_oauth2_server", "vendor": "ash-project", "versions": [{"lessThan": "268b591261a3473ab9b87272963e4dd2fd99d972", "status": "affected", "version": "e713a9ba816761140c226e2ca55b75c0b93f5984", "versionType": "git"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>Reachable only when Client ID Metadata Documents are enabled (<code>cimd_enabled?: true</code>), so the authorize endpoint fetches attacker-suppliable metadata URLs, and an internal or loopback target resolves to one of the affected IPv6 address forms.</p>"}, {"base64": false, "type": "text/markdown", "value": "Reachable only when Client ID Metadata Documents are enabled (`cimd_enabled?: true`), so the authorize endpoint fetches attacker-suppliable metadata URLs, and an internal or loopback target resolves to one of the affected IPv6 address forms."}], "value": "Reachable only when Client ID Metadata Documents are enabled (cimd_enabled?: true), so the authorize endpoint fetches attacker-suppliable metadata URLs, and an internal or loopback target resolves to one of the affected IPv6 address forms."}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:ash-project:ash_authentication_oauth2_server:*:*:*:*:*:*:*:*", "versionEndExcluding": "0.3.1", "versionStartIncluding": "0.3.0", "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>Server-Side Request Forgery (SSRF) vulnerability in ash-project ash_authentication_oauth2_server allows an attacker who controls a client metadata URL and its DNS to make the server connect to internal or loopback addresses.</p>\n<p><code>public_ip?/1</code> in <code>AshAuthentication.Oauth2Server.CIMD.ReqFetcher</code> enforces the outbound policy for CIMD metadata fetches. It classified several address forms as publicly routable that are not: IPv4-compatible <code>::/96</code> (for example <code>::127.0.0.1</code>), SIIT IPv4-translated <code>::ffff:0:0:0/96</code>, and deprecated site-local <code>fec0::/10</code>. A returned AAAA record in one of these ranges passed the policy, so a fetch pinned to that address reached space the policy was meant to block.</p>\n<p>This issue affects ash_authentication_oauth2_server: from 0.3.0 before 0.3.1.</p>"}, {"base64": false, "type": "text/markdown", "value": "Server-Side Request Forgery (SSRF) vulnerability in ash-project ash_authentication_oauth2_server allows an attacker who controls a client metadata URL and its DNS to make the server connect to internal or loopback addresses.\n\n`public_ip?/1` in `AshAuthentication.Oauth2Server.CIMD.ReqFetcher` enforces the outbound policy for CIMD metadata fetches. It classified several address forms as publicly routable that are not: IPv4-compatible `::/96` (for example `::127.0.0.1`), SIIT IPv4-translated `::ffff:0:0:0/96`, and deprecated site-local `fec0::/10`. A returned AAAA record in one of these ranges passed the policy, so a fetch pinned to that address reached space the policy was meant to block.\n\nThis issue affects ash_authentication_oauth2_server: from 0.3.0 before 0.3.1."}], "value": "Server-Side Request Forgery (SSRF) vulnerability in ash-project ash_authentication_oauth2_server allows an attacker who controls a client metadata URL and its DNS to make the server connect to internal or loopback addresses.\n\npublic_ip?/1 in AshAuthentication.Oauth2Server.CIMD.ReqFetcher enforces the outbound policy for CIMD metadata fetches. It classified several address forms as publicly routable that are not: IPv4-compatible ::/96 (for example ::127.0.0.1), SIIT IPv4-translated ::ffff:0:0:0/96, and deprecated site-local fec0::/10. A returned AAAA record in one of these ranges passed the policy, so a fetch pinned to that address reached space the policy was meant to block.\n\nThis issue affects ash_authentication_oauth2_server: from 0.3.0 before 0.3.1."}], "impacts": [{"capecId": "CAPEC-664", "descriptions": [{"lang": "en", "value": "CAPEC-664 Server Side Request Forgery"}]}], "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": "LOW", "subIntegrityImpact": "NONE", "userInteraction": "NONE", "valueDensity": "NOT_DEFINED", "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N", "version": "4.0", "vulnAvailabilityImpact": "NONE", "vulnConfidentialityImpact": "NONE", "vulnIntegrityImpact": "NONE", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-918", "description": "CWE-918 Server-Side Request Forgery (SSRF)", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-09-07T22:31:34.656Z"}, "references": [{"tags": ["vendor-advisory", "related"], "url": "https://github.com/ash-project/ash_authentication_oauth2_server/security/advisories/GHSA-wprp-8gvj-p6cv"}, {"tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-82757.html"}, {"tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82757"}, {"tags": ["patch"], "url": "https://github.com/ash-project/ash_authentication_oauth2_server/commit/268b591261a3473ab9b87272963e4dd2fd99d972"}], "source": {"discovery": "EXTERNAL"}, "title": "ash_authentication_oauth2_server CIMD fetcher classifies IPv4-in-IPv6 and site-local addresses as public, allowing SSRF"}}}

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