CVE-2026-82738 Ash.Type.UUIDv7 accepts non-v7 UUIDs that then fail to load, causing persistent denial of service
Attackers can permanently deny access to records by storing invalid UUIDs, causing persistent read failures in the Ash framework.
- 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-2026-82738?
CVE-2026-82738 is a medium-severity denial of service 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 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.cast_input/2 accepts any well-formed UUID string, including non-version-7 UUIDs, and stores it as a 16-byte binary. On read, cast_stored/2 (lib/ash/type/uuid_v7.ex) routes the stored binary back through cast_input/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 cast_stored/2.
This issue affects ash: from 3.6.3 before 3.32.2.
Weakness: CWE-20
Which versions are affected by CVE-2026-82738?
1 open source package ship an affected version, including ash.
| Package | Affected | Fixed in |
|---|---|---|
ash Hex | From 3.6.3 | 3.32.2 |
How do I fix CVE-2026-82738?
Upgrade ash to 3.32.2 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-2026-82738 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-82738 exists.
Sources
Also known as EEF-CVE-2026-82738, GHSA-7xfw-9jwm-9c4c.