CVE-2026-103474 yii2-starter-kit - Unrestricted File Upload

yii2-starter-kit <= 4.2.0 contains an unrestricted file upload caused by failure to validate file types in backend storage upload actions, letting authenticated managers upload and execute arbitrary PHP code, exploit requires manager role.

CVSS base score 8.8 /10
High
CISA KEV
Not listed
Public exploit
None known
Authentication
Required
EPSS
0.39% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Unrestricted File Upload
Impact
Remote Code Execution
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Published
30 September 2026
Updated
15 October 2026
Weakness
CWE-434

Vendor fix

Update to a version later than 4.2.0 or apply patches that validate file types properly.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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