What’s Vulnerable › Vulnerabilities

CVE-2026-103474: yii2-starter-kit through 4.2.0 Unrestricted File Upload RCE

• Severity: high (CVSS 8.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.4% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-09-30 · updated 2026-09-30
• Weakness: CWE-434

Description

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.

Affected products

• yii2-starter-kit: through 4.2.0

References

• https://github.com/yii-starter-kit/yii2-starter-kit
• https://github.com/yii-starter-kit/yii2-starter-kit/blob/cc2c451e8c959c7300b04efea597706a38609f58/backend/modules/file/controllers/StorageController.php#L36
• https://github.com/yii-starter-kit/yii2-starter-kit/issues/797
• https://www.vulncheck.com/advisories/yii2-starter-kit-through-4.2.0-unrestricted-file-upload-rce

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