CVE-2026-56384

21.06.2026, 14:16

Craft CMS contains a missing authorization vulnerability in the assets/preview-thumb endpoint. A Control Panel user without permission to view a target private asset can call the endpoint with an attacker-controlled assetId and receive preview HTML containing a signed fallback transform preview link for that private asset, because no asset-view permission check is performed before preview generation. This affects versions >= 4.0.0-RC1, <= 4.17.7 and >= 5.0.0-RC1, <= 5.9.13, and is fixed in 4.17.8 and 5.9.14.

Provider	Type	Base Score	Atk. Vector	Atk. Complexity	Priv. Required	Vector
NIST	Primary	4.3 MEDIUM	NETWORK	LOW	LOW	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Awaiting analysis

This vulnerability is currently awaiting analysis.

Base Score

CVSS 3.x

EPSS Score

Percentile: Unknown

Common Weakness Enumeration

CWE-862 - Missing Authorization
The software does not perform an authorization check when an actor attempts to access a resource or perform an action.

References

https://github.com/craftcms/cms/commit/d30df3112220db1ffd6726a3ed11857014c7fb27

https://github.com/craftcms/cms/security/advisories/GHSA-x76w-8c62-48mg

https://www.vulncheck.com/advisories/craft-cms-missing-authorization-in-assets-preview-thumb-endpoint