Concrete CMS up to 9.5.0 File Upload ptComposerFormLayoutSetControlCustomTemplate php file inclusion

Summaryinfo

A vulnerability marked as problematic has been reported in Concrete CMS up to 9.5.0. The impacted element is an unknown function of the component File Upload Handler. The manipulation of the argument ptComposerFormLayoutSetControlCustomTemplate leads to php file inclusion. This vulnerability is referenced as CVE-2026-8134. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Concrete CMS up to 9.5.0. It has been rated as problematic. This issue affects an unknown code of the component File Upload Handler. The manipulation of the argument ptComposerFormLayoutSetControlCustomTemplate with an unknown input leads to a php file inclusion vulnerability. Using CWE to declare the problem leads to CWE-98. The PHP application receives input from an upstream component, but it does not restrict or incorrectly restricts the input before its usage in "require," "include," or similar functions. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

Concrete CMS 9.5.0 and below fails to sanitize path traversal sequences in the ptComposerFormLayoutSetControlCustomTemplate field when saving page type composer form layouts. An authenticated rogue administrator with composer form editing rights can exploit this to include arbitrary readable files on the server. Combined with the file uploader's extension-only validation (which permits PHP code in files saved with image extensions like .png), this can result in authenticated remote code execution. The Concrete CMS security team gave this vulnerability a CVSS v.4.0 score of 9.4 with vector CVSS:4.0/AV:N/AC:L/AT:N/PR:H/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H   Thanks Yonatan Drori (Tenzai) for reporting.

The weakness was published by Yonatan Drori. It is possible to read the advisory at documentation.concretecms.org. The identification of this vulnerability is CVE-2026-8134 since 05/07/2026. The exploitation is known to be easy. The attack may be initiated remotely. The exploitation requires an enhanced level of successful authentication. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 05/22/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-31335). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

Type

• Content Management System

Vendor

• Concrete

Name

• CMS

Version

• 9.0
• 9.1
• 9.2
• 9.3
• 9.4
• 9.5.0

License

• open-source

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Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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