CVE-2026-82724Broken access control in AshPhoenix SubdomainHook via a nil tenant in handle_subdomain

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.

CVSS

7.6 HIGH (v4.0, CNA)CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

Weakness (CWE)

CWE-863

Known exploited

Not in CISA's KEV catalog

EPSS (exploitation in the next 30 days)

Not loaded for this CVE

Assigned by

EEF

NVD analysis

Deferred

Record last updated

Aug 31, 2026

First seen by InfoSec Signals

Oct 9, 2026

The CVE record on cve.org · NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.