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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
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.
Which versions are affected by CVE-2026-34593?
2 open source packages ship an affected version, including ash. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
ash Hex | All versions | 3.22.0 |
ash Hex | All versions | 3.22.0 |
Products include Ash-Hq Ash Framework.
How do I fix CVE-2026-34593?
Upgrade ash to 3.22.0 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
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
Sources
Also known as GHSA-jjf9-w5vj-r6vp.