What’s Vulnerable › Vulnerabilities

CVE-2026-82742: Ash.Filter.Runtime materializes a combinatorial cross-product over to-many relationships, exhausting memory

• Severity: medium (CVSS 5.9 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: 2026-09-01 · updated 2026-09-01
• Weakness: CWE-400

Description

Uncontrolled Resource Consumption vulnerability in ash-project ash lets an attacker exhaust node memory by matching a filter that spans multiple to-many relationships in memory. Ash.Filter.Runtime matches a filter against an in-memory record by first expanding the record into combinations of its related rows. flatten_relationships/2 (lib/ash/filter/runtime.ex) eagerly built the full Cartesian product across the filter's to-many relationship paths, so a record with K to-many relationships of M rows each materialized on the order of M^K scenarios before any predicate was checked. A filter or dataset that reaches several sizeable to-many relationships therefore allocates memory combinatorially and can exhaust the node. The fix streams the expansion lazily and short-circuits on the first matching scenario, bounding the work. This issue affects ash: from 1.29.0-rc0 before 3.32.2.

Affected products

• ash-project ash: from 1.29.0-rc0 before 3.32.2 — fixed in 3.32.2

How to fix

Upgrade to a fixed version: ash-project ash 3.32.2. Check the vendor advisory for mitigations.

References

• https://cna.erlef.org/cves/CVE-2026-82742.html
• https://github.com/ash-project/ash/commit/da07f009e889819ec410fa1f0f12534bfb9e21dd
• https://github.com/ash-project/ash/security/advisories/GHSA-mgwj-c69v-6f83
• https://osv.dev/vulnerability/EEF-CVE-2026-82742

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