CVE-2025-48300: Groundhogg File Upload RCE Vulnerability

CVE-2025-48300 Overview

CVE-2025-48300 is an Unrestricted Upload of File with Dangerous Type vulnerability (CWE-434) affecting the Groundhogg WordPress plugin developed by Adrian Tobey. This vulnerability allows attackers to upload a web shell to a web server, potentially leading to complete server compromise. The flaw exists in Groundhogg versions up to and including 4.2.1.

Groundhogg is a popular WordPress marketing automation and CRM plugin used by businesses to manage email marketing campaigns, customer relationships, and sales funnels. The unrestricted file upload vulnerability presents a significant risk as it enables attackers to bypass security controls and execute arbitrary code on affected WordPress installations.

Critical Impact

Attackers can upload malicious web shells to WordPress servers running vulnerable versions of Groundhogg, enabling remote code execution, data theft, and complete server takeover.

Affected Products

• Groundhogg WordPress Plugin versions up to and including 4.2.1
• WordPress installations with the vulnerable Groundhogg plugin installed
• Web servers hosting affected WordPress sites

Discovery Timeline

• 2025-07-16 - CVE-2025-48300 published to NVD
• 2026-04-01 - Last updated in NVD database

Technical Details for CVE-2025-48300

Vulnerability Analysis

This vulnerability stems from insufficient file type validation within the Groundhogg plugin's file upload functionality. The plugin fails to properly restrict the types of files that can be uploaded through its interfaces, allowing attackers to bypass intended security controls and upload files with dangerous extensions such as .php, .phtml, or other executable file types.

Web shell upload vulnerabilities are particularly dangerous in WordPress environments because uploaded files are typically stored in publicly accessible directories within the wp-content folder structure. Once a malicious PHP file is uploaded, an attacker can directly access it via HTTP request, triggering execution of the embedded malicious code with the privileges of the web server process.

Root Cause

The root cause of CVE-2025-48300 is the absence or improper implementation of file type validation in the Groundhogg plugin's upload handling routines. Specifically, the vulnerability likely involves:

• Missing server-side validation of file extensions and MIME types
• Reliance on client-side validation that can be easily bypassed
• Failure to implement a whitelist approach for allowed file types
• Insufficient sanitization of uploaded file names and content

This allows attackers to craft HTTP requests that upload executable PHP files disguised or presented directly as malicious scripts, bypassing any front-end restrictions.

Attack Vector

The attack vector for this vulnerability involves authenticated or potentially unauthenticated access to the Groundhogg plugin's file upload functionality. An attacker would typically:

1. Identify a WordPress installation running a vulnerable version of Groundhogg (<= 4.2.1)
2. Locate the file upload endpoint within the plugin's functionality
3. Craft a malicious PHP web shell file containing backdoor code
4. Upload the web shell through the vulnerable endpoint, bypassing file type restrictions
5. Access the uploaded web shell via direct HTTP request to execute commands on the server

Once the web shell is in place, attackers gain the ability to execute arbitrary system commands, exfiltrate sensitive data, modify website content, create additional backdoor accounts, pivot to other systems on the network, or use the compromised server for further attacks.

The vulnerability mechanism involves insufficient validation of uploaded file content and extensions. Attackers exploit this by crafting HTTP multipart/form-data requests containing malicious PHP files. For detailed technical information about this vulnerability, refer to the Patchstack WordPress Vulnerability Report.

Detection Methods for CVE-2025-48300

Indicators of Compromise

• Unexpected PHP files appearing in WordPress upload directories, particularly within wp-content/uploads/groundhogg/ or similar plugin-specific folders
• Web server access logs showing requests to unusual PHP files in upload directories with parameters commonly associated with web shells (e.g., cmd, exec, shell)
• Suspicious file creation timestamps that don't align with normal content management activities
• Outbound network connections from the web server process to unknown external IP addresses

Detection Strategies

• Monitor WordPress file system integrity using security plugins or host-based intrusion detection systems (HIDS) to detect unauthorized file creations
• Implement web application firewall (WAF) rules to detect and block file upload attempts containing PHP code or suspicious file extensions
• Review web server access logs for POST requests to Groundhogg plugin endpoints followed by GET requests to newly created files
• Deploy endpoint detection and response (EDR) solutions to monitor for web shell indicators and suspicious process spawning from web server processes

Monitoring Recommendations

• Enable detailed logging for WordPress file uploads and monitor for anomalous patterns including unexpected file types or sizes
• Configure alerts for new file creation events in WordPress plugin directories, particularly executable file types
• Implement network monitoring to detect command and control (C2) traffic patterns commonly associated with web shell activity

How to Mitigate CVE-2025-48300

Immediate Actions Required

• Update Groundhogg plugin to a version newer than 4.2.1 that addresses this vulnerability
• Audit WordPress installations for any suspicious PHP files in upload directories and remove any identified web shells
• Review web server access logs for signs of exploitation and investigate any suspicious file upload activity
• Consider temporarily disabling the Groundhogg plugin if an immediate update is not available

Patch Information

Organizations should update the Groundhogg WordPress plugin to the latest available version that addresses this arbitrary file upload vulnerability. The vulnerability affects versions up to and including 4.2.1. For the most current patch information and security updates, consult the Patchstack WordPress Vulnerability Report.

Workarounds

• Implement server-level restrictions to prevent PHP execution in WordPress upload directories using web server configuration
• Deploy a web application firewall (WAF) with rules to block suspicious file upload attempts
• Restrict access to WordPress admin areas and plugin functionality to trusted IP addresses where feasible
• Implement strict file type validation at the web server level as an additional layer of defense

# Apache configuration to prevent PHP execution in uploads directory
# Add to .htaccess in wp-content/uploads/ or in Apache vhost configuration
<Directory "/var/www/html/wp-content/uploads">
    <FilesMatch "\.(?:php|phtml|php[0-9]|phar)$">
        Require all denied
    </FilesMatch>
</Directory>

# Nginx configuration alternative
# Add to server block
location ~* /wp-content/uploads/.*\.php$ {
    deny all;
}