Divi Engine Divi Form Builder Plugin up to 5.1.8 on WordPress PHP File de_fb_uploads do_image_upload acceptFileTypes unrestricted upload

Summaryinfo

A vulnerability classified as critical was found in Divi Engine Divi Form Builder Plugin up to 5.1.8 on WordPress. This vulnerability affects the function do_image_upload of the file /wp-content/uploads/de_fb_uploads of the component PHP File Handler. Executing a manipulation of the argument acceptFileTypes can lead to unrestricted upload. This vulnerability appears as CVE-2026-5524. The attack may be performed from remote. There is no available exploit. Upgrading the affected component is advised.

Detailsinfo

A vulnerability was found in Divi Engine Divi Form Builder Plugin up to 5.1.8 on WordPress. It has been declared as critical. This vulnerability affects the function do_image_upload of the file /wp-content/uploads/de_fb_uploads of the component PHP File Handler. The manipulation of the argument acceptFileTypes with an unknown input leads to a unrestricted upload vulnerability. The CWE definition for the vulnerability is CWE-434. The product allows the attacker to upload or transfer files of dangerous types that can be automatically processed within the product's environment. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

The Divi Form Builder plugin for WordPress is vulnerable to Arbitrary File Upload leading to Remote Code Execution in all versions up to and including 5.1.8. This is due to insufficient file extension validation in the do_image_upload() function where user-supplied input from the acceptFileTypes POST parameter is directly interpolated into a regular expression used to validate uploaded files. Attackers can specify PHP-executable extensions such as .phtml, .phar, .php5, or .php7 to bypass the plugin's .htaccess protection which only blocks .php files specifically. Additionally, on Nginx-based servers, the .htaccess protection is completely ineffective as Nginx does not process .htaccess files. This makes it possible for unauthenticated attackers (who can obtain a nonce from any public page containing a form) to upload executable PHP files to the publicly accessible /wp-content/uploads/de_fb_uploads/ directory and achieve Remote Code Execution by accessing the uploaded file via HTTP. The vulnerability was partially patched in version 5.1.3.

The weakness was presented by 0xd4rk5id3. The advisory is shared for download at wordfence.com. This vulnerability was named CVE-2026-5524 since 04/04/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1608.002.

Upgrading eliminates this vulnerability. The upgrade is hosted for download at diviengine.com.

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Productinfo

Type

• WordPress Plugin

Vendor

• Divi Engine

Name

• Divi Form Builder Plugin

Version

• 5.1.0
• 5.1.1
• 5.1.2
• 5.1.3
• 5.1.4
• 5.1.5
• 5.1.6
• 5.1.7
• 5.1.8

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