---
id: CVE-2026-103474
title: >-
  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
summary: >-
  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 dire…
severity: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-434
vendor: yii2-starter-kit
product: yii2-starter-kit
affected:
  - yii2-starter-kit <= 4.2.0
published: '2026-09-30'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T19:08:43.927'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-103474'
references:
  - url: 'https://github.com/yii-starter-kit/yii2-starter-kit'
    label: disclosure@vulncheck.com
  - url: >-
      https://github.com/yii-starter-kit/yii2-starter-kit/blob/cc2c451e8c959c7300b04efea597706a38609f58/backend/modules/file/controllers/StorageController.php#L36
    label: disclosure@vulncheck.com
  - url: 'https://github.com/yii-starter-kit/yii2-starter-kit/issues/797'
    label: disclosure@vulncheck.com
  - url: >-
      https://www.vulncheck.com/advisories/yii2-starter-kit-through-4.2.0-unrestricted-file-upload-rce
    label: disclosure@vulncheck.com
tags:
  - nvd
  - cve.org
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-30T17:44:26.126873Z'
ingestedAt: '2026-09-30T18:17:24.539Z'
---

## Overview

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.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.