CVE-2026-103474 [HIGH] – yii2-starter-kit through 4.2.0 fails to validate file types in the backend storage upload

yii2-starter-kit through 4.2.0 fails to validate file types in the backend storage upload actions, allowing authenticated managers to upload PHP files. Attackers with manager role can upload PHP scripts to the web-accessible storage directory and request them to execute arbitrary code on the server.