EEF-CVE-2026-70395

Predicate injection in manage_relationship belongs_to lookup discloses secret lookup keys in Ash

## Summary Improper Neutralization of Special Elements in Data Query Logic vulnerability in ash-project ash allows an attacker to forge a relationship to a record they cannot name, and to recover the secret value used to look it up. When `manage_relationship` is used with `on_lookup: :relate` on a `belongs_to` relationship, the client-supplied lookup value is passed to `Ash.Query.filter/2` without being cast to the attribute type. A nested map submitted where a scalar is expected is therefore interpreted as a filter predicate rather than a literal, so a lookup for a specific record becomes a query for any record matching a condition. The same path omits `Ash.Query.limit(1)`, leaving `Ash.read_one/2` able to distinguish no match from one match from several, which turns comparison predicates into an oracle for the lookup value. Authorization is unaffected; the destination read policy still applies. This issue affects ash: from 1.52.0-rc.11 before 3.31.1. ## Configurations A `belongs_to` relationship must be managed with `manage_relationship` using `on_lookup: :relate`, and the lookup value must come from client input.