CVE-2026-82740 Ash.Type ignores outer array constraints on nested {:array, {:array, type}} inputs
Attackers can bypass validation to persist invalid nested array data in Ash applications, requiring an upgrade to the Ash library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-82740?
CVE-2026-82740 is a low-severity 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
Improper Input Validation vulnerability in ash-project ash fails to enforce the outer array constraints on a doubly-nested {:array, {:array, type}} attribute, letting invalid input pass validation.
Ash.Type.apply_constraints/3 (lib/ash/type/type.ex) handled the {:array, {:array, type}} case by mapping only the inner {:array, type} constraints over each element, so constraints declared on the outer array (such as min_length, max_length, and nil_items?) were never applied. An attacker could submit an outer list that violates those constraints (too many elements, or nil entries where disallowed) and have it accepted and persisted. The fix enforces the outer array constraints and adds explicit handling for nil and non-list inputs.
This issue affects ash: from 2.16.1 before 3.32.2.
Weakness: CWE-20
Which versions are affected by CVE-2026-82740?
1 open source package ship an affected version, including ash.
| Package | Affected | Fixed in |
|---|---|---|
ash Hex | From 2.16.1 | 3.32.2 |
How do I fix CVE-2026-82740?
Upgrade ash to 3.32.2 or later.
Is CVE-2026-82740 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82740 exists.
Sources
Also known as EEF-CVE-2026-82740, GHSA-v29m-p28g-w5fc.