Arbitrary file upload in Craft CMS

Published: 2018-01-02
Risk Medium
Patch available YES
Number of vulnerabilities 1
CVE-ID CVE-2018-3814
Exploitation vector Network
Public exploit N/A
Vulnerable software
Craft CMS
Web applications / CMS

Vendor Pixel & Tonic, Inc.

Security Bulletin

This security bulletin contains one medium risk vulnerability.

1) Arbitrary file upload


Risk: Medium

CVSSv3.1: 7.7 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2018-3814

CWE-ID: CWE-434 - Unrestricted Upload of File with Dangerous Type

Exploit availability: No


The vulnerability allows a remote attacker to execute arbitrary PHP code on the target system.

The vulnerability exists due to insufficient validation of user-supplied data when uploading files via "Assets->Upload files" screen. A remote authenticated attacker can upload .jpg file with PHP code inside, then use the "Replace it" option to rename the file and add .php extension to it. As a result the uploaded PHP code will be executed on the server.


Install update from vendor's repository.

Vulnerable software versions

Craft CMS: 2.6.3000

External links

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.