Arbitrary file upload in Yii2-Starter-Kit
CVE-2026-103474
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.
Vulnerability class: Unrestricted File Upload
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/yii-starter-kit/yii2-starter-kit/issues/797 (issue-tracking)
- github.com/yii-starter-kit/yii2-starter-kit (product)
- github.com/yii-starter-kit/yii2-starter-kit/blob/cc2c451e8c959c7300b04efea59770… (technical-description)
- www.vulncheck.com/advisories/yii2-starter-kit-through-4.2.0-unrestricted-file-u… (third-party-advisory)
Frequently asked questions
- What is CVE-2026-103474?
- CVE-2026-103474 is a high-severity vulnerability in Yii2-Starter-Kit, classified under Unrestricted Upload of File with Dangerous Type. CVSS score: 8.8/10. Published 2026-09-30.
- How severe is CVE-2026-103474?
- High severity. CVSS v3 base score is 8.8 out of 10.