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Medium · 5.9 CVE-2026-82735 EEF-CVE-2026-82735EUVD-2026-68962GHSA-mq7g-pffw-m8xh

Match regex runs on over-length input in Ash.Type.String, enabling regex denial of service

Published Sep 1, 2026 · Updated Sep 1, 2026 · Assigned by EEF

Description

Uncontrolled Resource Consumption vulnerability in ash-project ash allows an attacker to force an expensive regular expression to run on input that a length constraint should have already rejected.

Ash.Type.String.apply_constraints/2 (lib/ash/type/string.ex) evaluated the :match regex regardless of the min_length and max_length constraints on the same attribute. Because the length check did not gate the regex, an over-length value that the length constraint rejects still had the pattern applied to it, so the length limit that would otherwise bound the work never constrained the regex input. Against a backtracking pattern this yields catastrophic regex evaluation on attacker-sized input, and even a linear pattern runs on arbitrarily large input, consuming CPU per request. The fix skips the :match regex whenever a length constraint is violated, making the two checks order-independent.

This issue affects ash: from 0.10.0 before 3.32.2.

Affected products

VendorProductAffectedFixed
ash-project ash 0.10.0 – < 3.32.2 3.32.2

Affected packages

EcosystemPackageAffectedFixedRecord
Hex ash >= 0.10.0, < 3.32.2 3.32.2 EEF-CVE-2026-82735

References