/Vulnerability Library

Divi Form Builder <=5.1.8 - Unauthenticated Arbitrary File Upload RCE

CVE-2026-5524
Verified

Description

The Divi Form Builder plugin for WordPress versions 5.1.8 and prior contains an unauthenticated arbitrary file upload vulnerability in the do_image_upload() AJAX handler. The user-controlled acceptFileTypes POST parameter is injected unsanitized into a PHP regex for file extension validation. By supplying acceptFileTypes=phtml the constructed regex accepts .phtml files while the plugin's .htaccess only blocks .php, so Apache executes .phtml files as PHP. The required nonce (fb_nonce) is publicly embedded in any page containing a Divi form via the de_fb_obj JavaScript object. Uploaded shells land in /wp-content/uploads/de_fb_uploads/. Fixed in 5.1.9.

Severity

Critical

CVSS Score

9.8

Exploit Probability

3%

Affected Product

divi-form-builder

Published Date

September 14, 2026

Template Author

dhiyaneshdk

CVE-2026-5524.yaml
9.8Score

CVSS Metrics

CVSS Vector:
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVE ID:
cve-2026-5524
CWE ID:
cwe-434

References

https://nvd.nist.gov/vuln/detail/CVE-2026-5524https://github.com/caterscam/CVE-2026-5524-PoChttps://wpscan.com/vulnerability/CVE-2026-5524

Remediation Steps

Update the Divi Form Builder plugin to version 5.1.9 or later, which validates file extensions without relying on the user-controlled acceptFileTypes parameter.