{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-82726", "assignerOrgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "state": "PUBLISHED", "assignerShortName": "EEF", "dateReserved": "2026-08-31T00:59:08.960Z", "datePublished": "2026-08-31T03:05:38.612Z", "dateUpdated": "2026-08-31T03:05:38.612Z"}, "containers": {"cna": {"affected": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:ash-project:ash_phoenix:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.AshPhoenix.Helpers'"], "packageName": "ash_phoenix", "packageURL": "pkg:hex/ash_phoenix", "product": "ash_phoenix", "programFiles": ["lib/ash_phoenix/helpers.ex"], "programRoutines": [{"name": "'Elixir.AshPhoenix.Helpers':get_subdomain/2"}], "repo": "https://github.com/ash-project/ash_phoenix", "vendor": "ash-project", "versions": [{"lessThan": "2.3.25", "status": "affected", "version": "2.1.26", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:ash-project:ash_phoenix:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.AshPhoenix.Helpers'"], "packageName": "ash-project/ash_phoenix", "packageURL": "pkg:github/ash-project/ash_phoenix", "product": "ash_phoenix", "programFiles": ["lib/ash_phoenix/helpers.ex"], "programRoutines": [{"name": "'Elixir.AshPhoenix.Helpers':get_subdomain/2"}], "repo": "https://github.com/ash-project/ash_phoenix", "vendor": "ash-project", "versions": [{"lessThan": "8306f29e77526840c89f3cd244996ce7c0fa2cda", "status": "affected", "version": "9a5ea4d377bc263de321d79574872a3dfc4fb541", "versionType": "git"}]}], "configurations": [{"lang": "en", "supportingMedia": [{"base64": false, "type": "text/html", "value": "<p>The application uses subdomain-based multitenancy via <code>AshPhoenix.Helpers.get_subdomain/2</code> (for example through <code>AshPhoenix.LiveView.SubdomainHook</code>) to select the tenant from the request host.</p>"}, {"base64": false, "type": "text/markdown", "value": "The application uses subdomain-based multitenancy via `AshPhoenix.Helpers.get_subdomain/2` (for example through `AshPhoenix.LiveView.SubdomainHook`) to select the tenant from the request host."}], "value": "The application uses subdomain-based multitenancy via AshPhoenix.Helpers.get_subdomain/2 (for example through AshPhoenix.LiveView.SubdomainHook) to select the tenant from the request host."}], "cpeApplicability": [{"nodes": [{"cpeMatch": [{"criteria": "cpe:2.3:a:ash-project:ash_phoenix:*:*:*:*:*:*:*:*", "versionEndExcluding": "2.3.25", "versionStartIncluding": "2.1.26", "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>Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote client select the tenant an Ash application uses, or degrade the request, by sending a crafted <code>Host</code> header.</p>\n<p><code>AshPhoenix.Helpers.get_subdomain/2</code> stripped the root domain with <code>String.replace(host, ~r/.?#{root_host}/, \"\")</code>. The root host was interpolated raw, so each <code>.</code> became a wildcard and any metacharacter a pattern, and the replace was global and unanchored, so a match was removed from anywhere in the string. With <code>root_host</code> <code>example.com</code>, <code>Host: foo.exampleXcom.attacker.net</code> returned the tenant <code>foo.attacker.net</code>. A metacharacter-bearing or <code>nil</code> root host degraded the pattern or raised on every request. The comparison was also case-sensitive, so <code>TENANT.EXAMPLE.COM</code> and <code>EXAMPLE.COM</code> slipped past the root-host allowlist. <code>conn.host</code> comes from the client <code>Host</code> header. The fix matches the root host case-insensitively and only as an exact trailing suffix.</p>\n<p>This issue affects ash_phoenix: from 2.1.26 before 2.3.25.</p>"}, {"base64": false, "type": "text/markdown", "value": "Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote client select the tenant an Ash application uses, or degrade the request, by sending a crafted `Host` header.\n\n`AshPhoenix.Helpers.get_subdomain/2` stripped the root domain with `String.replace(host, ~r/.?#{root_host}/, \"\")`. The root host was interpolated raw, so each `.` became a wildcard and any metacharacter a pattern, and the replace was global and unanchored, so a match was removed from anywhere in the string. With `root_host` `example.com`, `Host: foo.exampleXcom.attacker.net` returned the tenant `foo.attacker.net`. A metacharacter-bearing or `nil` root host degraded the pattern or raised on every request. The comparison was also case-sensitive, so `TENANT.EXAMPLE.COM` and `EXAMPLE.COM` slipped past the root-host allowlist. `conn.host` comes from the client `Host` header. The fix matches the root host case-insensitively and only as an exact trailing suffix.\n\nThis issue affects ash_phoenix: from 2.1.26 before 2.3.25."}], "value": "Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote client select the tenant an Ash application uses, or degrade the request, by sending a crafted Host header.\n\nAshPhoenix.Helpers.get_subdomain/2 stripped the root domain with String.replace(host, ~r/.?#{root_host}/, \"\"). The root host was interpolated raw, so each . became a wildcard and any metacharacter a pattern, and the replace was global and unanchored, so a match was removed from anywhere in the string. With root_host example.com, Host: foo.exampleXcom.attacker.net returned the tenant foo.attacker.net. A metacharacter-bearing or nil root host degraded the pattern or raised on every request. The comparison was also case-sensitive, so TENANT.EXAMPLE.COM and EXAMPLE.COM slipped past the root-host allowlist. conn.host comes from the client Host header. The fix matches the root host case-insensitively and only as an exact trailing suffix.\n\nThis issue affects ash_phoenix: from 2.1.26 before 2.3.25."}], "impacts": [{"capecId": "CAPEC-153", "descriptions": [{"lang": "en", "value": "CAPEC-153 Input Data Manipulation"}]}], "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:L/VI:L/VA:L/SC:N/SI:N/SA:N", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-625", "description": "CWE-625 Permissive Regular Expression", "lang": "en", "type": "CWE"}]}, {"descriptions": [{"cweId": "CWE-178", "description": "CWE-178 Improper Handling of Case Sensitivity", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "shortName": "EEF", "dateUpdated": "2026-08-31T03:05:38.612Z"}, "references": [{"tags": ["vendor-advisory", "related"], "url": "https://github.com/ash-project/ash_phoenix/security/advisories/GHSA-rpf8-q9jh-qxrr"}, {"tags": ["related"], "url": "https://cna.erlef.org/cves/CVE-2026-82726.html"}, {"tags": ["related"], "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82726"}, {"tags": ["patch"], "url": "https://github.com/ash-project/ash_phoenix/commit/8306f29e77526840c89f3cd244996ce7c0fa2cda"}], "source": {"discovery": "EXTERNAL"}, "title": "AshPhoenix get_subdomain maps a crafted or differently-cased Host header to an arbitrary tenant"}}}

{}

{"affected": [{"affectedData": [{"collectionURL": "https://repo.hex.pm", "cpes": ["cpe:2.3:a:ash-project:ash_phoenix:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.AshPhoenix.Helpers'"], "packageName": "ash_phoenix", "packageURL": "pkg:hex/ash_phoenix", "product": "ash_phoenix", "programFiles": ["lib/ash_phoenix/helpers.ex"], "programRoutines": [{"name": "'Elixir.AshPhoenix.Helpers':get_subdomain/2"}], "repo": "https://github.com/ash-project/ash_phoenix", "vendor": "ash-project", "versions": [{"lessThan": "2.3.25", "status": "affected", "version": "2.1.26", "versionType": "semver"}]}, {"collectionURL": "https://github.com", "cpes": ["cpe:2.3:a:ash-project:ash_phoenix:*:*:*:*:*:*:*:*"], "defaultStatus": "unaffected", "modules": ["'Elixir.AshPhoenix.Helpers'"], "packageName": "ash-project/ash_phoenix", "packageURL": "pkg:github/ash-project/ash_phoenix", "product": "ash_phoenix", "programFiles": ["lib/ash_phoenix/helpers.ex"], "programRoutines": [{"name": "'Elixir.AshPhoenix.Helpers':get_subdomain/2"}], "repo": "https://github.com/ash-project/ash_phoenix", "vendor": "ash-project", "versions": [{"lessThan": "8306f29e77526840c89f3cd244996ce7c0fa2cda", "status": "affected", "version": "9a5ea4d377bc263de321d79574872a3dfc4fb541", "versionType": "git"}]}], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"}], "cveTags": [], "descriptions": [{"lang": "en", "value": "Permissive Regular Expression vulnerability in ash-project ash_phoenix lets a remote client select the tenant an Ash application uses, or degrade the request, by sending a crafted Host header.\n\nAshPhoenix.Helpers.get_subdomain/2 stripped the root domain with String.replace(host, ~r/.?#{root_host}/, \"\"). The root host was interpolated raw, so each . became a wildcard and any metacharacter a pattern, and the replace was global and unanchored, so a match was removed from anywhere in the string. With root_host example.com, Host: foo.exampleXcom.attacker.net returned the tenant foo.attacker.net. A metacharacter-bearing or nil root host degraded the pattern or raised on every request. The comparison was also case-sensitive, so TENANT.EXAMPLE.COM and EXAMPLE.COM slipped past the root-host allowlist. conn.host comes from the client Host header. The fix matches the root host case-insensitively and only as an exact trailing suffix.\n\nThis issue affects ash_phoenix: from 2.1.26 before 2.3.25."}], "id": "CVE-2026-82726", "lastModified": "2026-08-31T04:17:29.357", "metrics": {"cvssMetricV40": [{"cvssData": {"Automatable": "NOT_DEFINED", "Recovery": "NOT_DEFINED", "Safety": "NOT_DEFINED", "attackComplexity": "LOW", "attackRequirements": "PRESENT", "attackVector": "NETWORK", "availabilityRequirement": "NOT_DEFINED", "baseScore": 6.3, "baseSeverity": "MEDIUM", "confidentialityRequirement": "NOT_DEFINED", "exploitMaturity": "NOT_DEFINED", "integrityRequirement": "NOT_DEFINED", "modifiedAttackComplexity": "NOT_DEFINED", "modifiedAttackRequirements": "NOT_DEFINED", "modifiedAttackVector": "NOT_DEFINED", "modifiedPrivilegesRequired": "NOT_DEFINED", "modifiedSubAvailabilityImpact": "NOT_DEFINED", "modifiedSubConfidentialityImpact": "NOT_DEFINED", "modifiedSubIntegrityImpact": "NOT_DEFINED", "modifiedUserInteraction": "NOT_DEFINED", "modifiedVulnAvailabilityImpact": "NOT_DEFINED", "modifiedVulnConfidentialityImpact": "NOT_DEFINED", "modifiedVulnIntegrityImpact": "NOT_DEFINED", "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:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "version": "4.0", "vulnAvailabilityImpact": "LOW", "vulnConfidentialityImpact": "LOW", "vulnIntegrityImpact": "LOW", "vulnerabilityResponseEffort": "NOT_DEFINED"}, "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}]}, "published": "2026-08-31T04:17:29.357", "references": [{"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://cna.erlef.org/cves/CVE-2026-82726.html"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/ash-project/ash_phoenix/commit/8306f29e77526840c89f3cd244996ce7c0fa2cda"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://github.com/ash-project/ash_phoenix/security/advisories/GHSA-rpf8-q9jh-qxrr"}, {"source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "url": "https://osv.dev/vulnerability/EEF-CVE-2026-82726"}], "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-178"}, {"lang": "en", "value": "CWE-625"}], "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db", "type": "Secondary"}]}

{}

{}