CVE-2026-101028: Ash.count, Ash.exists and Ash.aggregate skip related resources' read policies in filters and sorts

Severity: medium (CVSS 6.0 v4.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-09 · updated 2026-10-09
Weakness: CWE-863

Description

Incorrect Authorization vulnerability in ash-project ash allows an actor to infer data in related records they cannot read via Ash.count/2, Ash.exists/2 and Ash.aggregate/3. Ash.Actions.Aggregate.run/4 (lib/ash/actions/aggregate.ex) applied only the root resource's read policy before running the aggregate query. The read path also applies each related resource's read policy to filter and sort references that cross a relationship, directly (for example comments.body) or through an aggregate over one, but the aggregate path skipped that step. A caller whose filter or sort reaches these functions, for example through Ash.Query.filter_input/2, an ash_lua script, or an AshAi tool offering count or exists results, can test conditions against related rows hidden from them and recover their existence and attribute values one query at a time. Ash.read/2 and its page counts are not affected. This issue affects ash: from 2.6.0 before 3.34.6.

Affected products

ash-project ash: from 2.6.0 before 3.34.6 — fixed in 3.34.6

How to fix

Upgrade to a fixed version: ash-project ash 3.34.6. Check the vendor advisory for mitigations.

References

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