Incorrect Authorization vulnerability in ash-project ash_phoenix invokes the SubdomainHook authorization callback with a nil tenant, so tenant-scoped access checks never see the tenant they are meant to enforce.
AshPhoenix.LiveView.SubdomainHook.on_mount/4 attached a handle_params hook to assign the tenant and then immediately called handle_subdomain in the same on_mount. The tenant assign is only written when LiveView later runs handle_params, strictly after on_mount returns, so handle_subdomain read an unset assign and ran as apply(m, f, [socket, nil | a]). A consumer gate that halts when the user does not belong to the tenant instead evaluated nil, either crashing or taking a permissive branch, and it was never re-run once the real subdomain was assigned or on later navigations. The fix runs handle_subdomain inside the handle_params hook with the real tenant on every navigation.
This issue affects ash_phoenix: from 2.1.26 before 2.3.25.
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"cveId": "CVE-2026-82724",
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"assignerShortName": "EEF",
"dateUpdated": "2026-08-31T03:07:57.455Z",
"dateReserved": "2026-08-31T00:59:08.960Z",
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"title": "Broken access control in AshPhoenix SubdomainHook via a nil tenant in handle_subdomain",
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"value": "Incorrect Authorization vulnerability in ash-project ash_phoenix invokes the SubdomainHook authorization callback with a nil tenant, so tenant-scoped access checks never see the tenant they are meant to enforce.\n\nAshPhoenix.LiveView.SubdomainHook.on_mount/4 attached a handle_params hook to assign the tenant and then immediately called handle_subdomain in the same on_mount. The tenant assign is only written when LiveView later runs handle_params, strictly after on_mount returns, so handle_subdomain read an unset assign and ran as apply(m, f, [socket, nil | a]). A consumer gate that halts when the user does not belong to the tenant instead evaluated nil, either crashing or taking a permissive branch, and it was never re-run once the real subdomain was assigned or on later navigations. The fix runs handle_subdomain inside the handle_params hook with the real tenant on every navigation.\n\nThis issue affects ash_phoenix: from 2.1.26 before 2.3.25.",
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"value": "<p>Incorrect Authorization vulnerability in ash-project ash_phoenix invokes the <code>SubdomainHook</code> authorization callback with a <code>nil</code> tenant, so tenant-scoped access checks never see the tenant they are meant to enforce.</p>\n<p><code>AshPhoenix.LiveView.SubdomainHook.on_mount/4</code> attached a <code>handle_params</code> hook to assign the tenant and then immediately called <code>handle_subdomain</code> in the same <code>on_mount</code>. The tenant assign is only written when LiveView later runs <code>handle_params</code>, strictly after <code>on_mount</code> returns, so <code>handle_subdomain</code> read an unset assign and ran as <code>apply(m, f, [socket, nil | a])</code>. A consumer gate that halts when the user does not belong to the tenant instead evaluated <code>nil</code>, either crashing or taking a permissive branch, and it was never re-run once the real subdomain was assigned or on later navigations. The fix runs <code>handle_subdomain</code> inside the <code>handle_params</code> hook with the real tenant on every navigation.</p>\n<p>This issue affects ash_phoenix: from 2.1.26 before 2.3.25.</p>"
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"value": "Incorrect Authorization vulnerability in ash-project ash_phoenix invokes the `SubdomainHook` authorization callback with a `nil` tenant, so tenant-scoped access checks never see the tenant they are meant to enforce.\n\n`AshPhoenix.LiveView.SubdomainHook.on_mount/4` attached a `handle_params` hook to assign the tenant and then immediately called `handle_subdomain` in the same `on_mount`. The tenant assign is only written when LiveView later runs `handle_params`, strictly after `on_mount` returns, so `handle_subdomain` read an unset assign and ran as `apply(m, f, [socket, nil | a])`. A consumer gate that halts when the user does not belong to the tenant instead evaluated `nil`, either crashing or taking a permissive branch, and it was never re-run once the real subdomain was assigned or on later navigations. The fix runs `handle_subdomain` inside the `handle_params` hook with the real tenant on every navigation.\n\nThis issue affects ash_phoenix: from 2.1.26 before 2.3.25."
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"affected": [
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"vendor": "ash-project",
"product": "ash_phoenix",
"collectionURL": "https://repo.hex.pm",
"packageName": "ash_phoenix",
"cpes": [
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"description": "CWE-863 Incorrect Authorization",
"cweId": "CWE-863",
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"url": "https://github.com/ash-project/ash_phoenix/security/advisories/GHSA-39c8-xcwr-gqff",
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"value": "The application uses AshPhoenix.LiveView.SubdomainHook with a handle_subdomain callback as a tenant-scoped authorization gate.",
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"credits": [
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"value": "Peter Ullrich",
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"value": "Peter Ullrich",
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