CVE-2026-70395: Predicate injection in manage_relationship belongs_to lookup discloses secret lookup keys in Ash

Severity: low (CVSS 2.1 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-08-09 · updated 2026-10-24
Weakness: CWE-943

Description

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.

Affected products

ash-project ash: from 1.52.0-rc.11 before 3.31.1 — fixed in 3.31.1

How to fix

Upgrade to a fixed version: ash-project ash 3.31.1. Check the vendor advisory for mitigations.

References

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