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

> Attackers can exhaust memory by triggering combinatorial expansion of to-many relationships in Ash.Filter.Runtime, causing denial of service.

- **Severity:** Medium 5.9 (`CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 Sep 2026
- **Updated:** 1 Sep 2026
- **Also known as:** EEF-CVE-2026-82742, GHSA-mgwj-c69v-6f83

## What is CVE-2026-82742?

CVE-2026-82742 is a medium-severity denial of service vulnerability in ash-project ash, published on 1 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-82742?

1 open source package ship an affected version, including ash.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash` | Hex | From 1.29.0-rc0 | 3.32.2 |

## How do I fix CVE-2026-82742?

Upgrade ash to 3.32.2 or later.

## Is CVE-2026-82742 being exploited?

There is no known exploitation of CVE-2026-82742 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-82742 and fix it if it is affected.

What it is: CVE-2026-82742 is a medium-severity denial of service vulnerability in ash-project ash, published on 1 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-82742 in the wild and no public exploit code.

Affected packages and fixed versions:
- ash (Hex): affected from 1.29.0-rc0; fixed in 3.32.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-82742/ (Markdown: https://insights.sbomify.com/CVE-2026-82742/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-82742
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-82742
- OSV: https://osv.dev/vulnerability/CVE-2026-82742

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-82742/
Summaries are generated and may contain mistakes; the official description above is the record.