CVE-2025-6679 Overview
The Bit Form builder plugin for WordPress is vulnerable to arbitrary file uploads due to missing file type validation in all versions up to, and including, 2.20.4. This vulnerability allows unauthenticated attackers to upload arbitrary files on the affected site's server, which may enable remote code execution. The vulnerability is exploitable when the PRO version is installed and activated, and a form with an advanced file upload element has been published.
Critical Impact
Unauthenticated attackers can achieve remote code execution by uploading malicious files to WordPress sites running vulnerable versions of Bit Form PRO with published forms containing advanced file upload elements.
Affected Products
- Bit Form builder plugin for WordPress versions up to and including 2.20.4
- Bit Form PRO version (required for exploitation)
- WordPress sites with published forms containing advanced file upload elements
Discovery Timeline
- August 15, 2025 - CVE-2025-6679 published to NVD
- August 15, 2025 - Last updated in NVD database
Technical Details for CVE-2025-6679
Vulnerability Analysis
This vulnerability is classified as CWE-434 (Unrestricted Upload of File with Dangerous Type). The Bit Form plugin fails to implement proper file type validation when processing uploads through the advanced file upload form element. This oversight allows attackers to bypass intended security restrictions and upload files with executable extensions such as .php, potentially leading to complete server compromise.
The vulnerability requires no authentication to exploit, making it particularly dangerous for public-facing WordPress installations. However, specific conditions must be met: the PRO version of Bit Form must be installed and activated, and at least one form with an advanced file upload element must be published and accessible.
Root Cause
The root cause of this vulnerability is the absence of file type validation in the advanced file upload handling functionality. The plugin fails to verify that uploaded files match expected or allowed file types before storing them on the server. Without this validation, the server accepts and stores any file type submitted through the form, including server-side scripts that can be executed by the web server.
Attack Vector
The attack can be executed remotely over the network without requiring any authentication or user interaction. An attacker identifies a WordPress site running a vulnerable version of Bit Form PRO with a published form containing the advanced file upload element. The attacker then crafts a malicious request to upload a PHP web shell or other malicious script through the file upload field. Once uploaded, the attacker accesses the uploaded file directly through the web server, triggering code execution with the privileges of the web server process.
The exploitation flow involves identifying vulnerable forms, crafting multipart form requests with malicious payloads disguised or submitted as uploads, and subsequently accessing the uploaded malicious files to achieve code execution.
Detection Methods for CVE-2025-6679
Indicators of Compromise
- Unexpected PHP or executable files appearing in WordPress upload directories
- Web server access logs showing requests to unusual file paths within wp-content/uploads/
- New or modified files with suspicious names in form upload directories
- Outbound network connections from the web server process to unknown destinations
Detection Strategies
- Monitor file system changes in WordPress upload directories for newly created executable files
- Implement web application firewall rules to inspect file upload requests for malicious content
- Review web server logs for access to uploaded files with executable extensions
- Deploy endpoint detection to identify web shell activity patterns on WordPress servers
Monitoring Recommendations
- Enable file integrity monitoring on all WordPress installation directories
- Configure alerts for new PHP files created in upload directories
- Monitor for anomalous process execution by the web server user account
- Review form submission logs for unusual file upload patterns
How to Mitigate CVE-2025-6679
Immediate Actions Required
- Update Bit Form plugin to the latest patched version immediately
- Audit existing upload directories for any suspicious or unexpected files
- Temporarily disable forms with advanced file upload elements until patching is complete
- Review web server access logs for potential exploitation attempts
Patch Information
A security patch addressing this vulnerability is available through the WordPress plugin repository. The fix implements proper file type validation for the advanced file upload functionality. For technical details on the changes, refer to the WordPress Plugin Changeset. Additional vulnerability analysis is available from Wordfence Threat Intelligence.
Workarounds
- Disable the advanced file upload element in all published forms until the patch can be applied
- Implement server-side file type validation at the web server level using .htaccess rules or equivalent configurations
- Restrict file uploads to specific MIME types at the web server configuration level
- Consider temporarily deactivating the Bit Form PRO plugin if immediate patching is not possible
# Apache .htaccess configuration to block PHP execution in uploads
<Directory "/path/to/wordpress/wp-content/uploads">
<FilesMatch "\.php$">
Require all denied
</FilesMatch>
</Directory>
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
