Craft CMS: Authenticated "assets/preview-thumb" discloses signed fallback transform preview link to CP users without asset-view permission

Summary A user with Control Panel access but without permission to view a target private asset can call assets/preview-thumb and receive preview HTML that contains a signed fallback transform link for that private asset. Details Root-cause analysis: 1. The endpoint accepts an attacker-controlled...

CVE-2026-56384

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...

CVE-2026-56384

Craft CMS has a missing authorization vulnerability in the assets/preview-thumb endpoint. A Control Panel user without permission to view a private asset can call the endpoint with an attacker-controlled assetId and receive preview HTML containing a signed fallback transform preview link for that...

CVE-2026-56384 Craft CMS - Missing Authorization in assets/preview-thumb Endpoint

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...

CVE-2026-56384 Craft CMS - Missing Authorization in assets/preview-thumb Endpoint

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...

PT-2026-51232

Name of the Vulnerable Software and Affected Versions Craft CMS versions 4.0.0-RC1 through 4.17.7 Craft CMS versions 5.0.0-RC1 through 5.9.13 Description A missing authorization issue exists in the 'assets/preview-thumb' endpoint. A Control Panel user lacking permissions to view a specific privat...