CVE-2026-82738

Ash.Type.UUIDv7 accepts non-v7 UUIDs that then fail to load, causing persistent denial of service

MEDIUM
5.9
CVSS Score
Published: September 1, 2026 at 03:26 AM UTC
Updated: September 1, 2026 at 09:31 PM UTC
1 product affected across 1 vendorAsh

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Severity
MEDIUM5.9
Exploit prediction
EPSS 0.2%
SSVC
PoC

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.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

90%
3.6.3 ≤ v < 3.32.23.6.3751d8a4d11564efbe358c90c8347f3a00eb60782
Vendor states this is fixed in c453cdc0b8570e86ffef0d10e136247f52b3ea76 (fixed)
Affected range stops below 3.32.2, so it looks safe — our inference, not a vendor statement

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCPoCNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

5.9MEDIUMEEF
Vector?

Quick Info

StatusDEFERRED
CWE
CWE-20

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