# CVE-2026-34593: Ash Framework: Ash.Type.Module.cast_input/2 atom exhaustion via unchecked Module.concat allows BEAM VM crash

> Attackers can crash the BEAM VM by exhausting the atom table through unchecked module name concatenation in Ash Framework.

- **Severity:** High 8.2 (`CVSS:4.0/AV:N/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:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 2 Apr 2026
- **Updated:** 3 Apr 2026
- **Also known as:** GHSA-jjf9-w5vj-r6vp

## What is CVE-2026-34593?

CVE-2026-34593 is a high-severity denial of service vulnerability in ash-project ash, published on 2 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Ash Framework is a declarative, extensible framework for building Elixir applications. Prior to version 3.22.0, Ash.Type.Module.cast_input/2 unconditionally creates a new Erlang atom via Module.concat([value]) for any user-supplied binary string that starts with "Elixir.", before verifying whether the referenced module exists. Because Erlang atoms are never garbage-collected and the BEAM atom table has a hard default limit of approximately 1,048,576 entries, an attacker who can submit values to any resource attribute or argument of type :module can exhaust this table and crash the entire BEAM VM, taking down the application. This issue has been patched in version 3.22.0.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2026-34593?

2 open source packages ship an affected version, including ash. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `ash` | Hex | All versions | 3.22.0 |
| `ash` | Hex | All versions | 3.22.0 |

Products: Ash-Hq Ash Framework.

## How do I fix CVE-2026-34593?

Upgrade ash to 3.22.0 or later.

## Is CVE-2026-34593 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34593 exists.

## Other vulnerabilities in ash-project ash

- [CVE-2026-67579](https://insights.sbomify.com/CVE-2026-67579/): Filter expression injection via forged keyset pagination cursor in Ash (high 7.5)
- [CVE-2026-69659](https://insights.sbomify.com/CVE-2026-69659/): Memory exhaustion via unbounded deserialization of keyset pagination cursors in Ash.Page.Keyset (medium 5.9)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-34593 and fix it if it is affected.

What it is: CVE-2026-34593 is a high-severity denial of service vulnerability in ash-project ash, published on 2 Apr 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-34593 exists.

Affected packages and fixed versions:
- ash (Hex): affected all versions; fixed in 3.22.0
- ash (Hex): affected all versions; fixed in 3.22.0

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-2026-34593/ (Markdown: https://insights.sbomify.com/CVE-2026-34593/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-34593
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-34593
- OSV: https://osv.dev/vulnerability/CVE-2026-34593

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-34593/
Summaries are generated and may contain mistakes; the official description above is the record.