CVE-2026-82738: Ash.Type.UUIDv7 accepts non-v7 UUIDs that then fail to load, causing persistent denial of service
Improper Input Validation vulnerability in ash-project ash allows an attacker to persistently deny reads of a record by storing a non-version-7 UUID in an Ash.Type.UUIDv7 attribute.
Ash.Type.UUIDv7.castinput/2 accepts any well-formed UUID string, including non-version-7 UUIDs, and stores it as a 16-byte binary. On read, caststored/2 (lib/ash/type/uuidv7.ex) routes the stored binary back through castinput/2, which since an input-validation tightening in v3.6.3 matches only version-7 (and optionally version-4) 16-byte binaries and otherwise expects a 36-character string. A stored non-v7 16-byte binary matches neither clause and returns :error, so every later read of that record fails. An attacker able to set such an attribute poisons the row permanently. The fix decodes any 16-byte stored binary directly in caststored/2.
This issue affects ash: from 3.6.3 before 3.32.2.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
ash-project/ashto a version that resolves this vulnerability.Fixed in 3.32.2 - Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.6.3 - Compensating control
Prevent untrusted users/inputs from being able to persistently set attributes of type Ash.Type.UUIDv7 (e.g., restrict/validate write access so attackers cannot store non-version-7 UUIDs in UUIDv7 attributes).