CVE-2026-82740: Input Validation Flaw

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.

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EPSS — Exploit Prediction

0.0013

Probability of exploitation

0.03%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-20 Improper Input Validation

References

Other References

https://cna.erlef.org/cves/CVE-2026-82740.html https://github.com/ash-project/ash/commit/c85ccff7dc6e3b0b3e40ad788b0056b3b6bee5ce https://github.com/ash-project/ash/security/advisories/GHSA-v29m-p28g-w5fc https://osv.dev/vulnerability/EEF-CVE-2026-82740 https://github.com/ash-project/ash/security/advisories/GHSA-v29m-p28g-w5fc

Frequently Asked Questions

What is CVE-2026-82740? +

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.

How do I check if I'm vulnerable to CVE-2026-82740? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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