CVE-2025-47530: WPFunnels Object Injection Vulnerability

CVE-2025-47530 Overview

CVE-2025-47530 is a critical PHP Object Injection vulnerability affecting the WPFunnels WordPress plugin. This insecure deserialization flaw allows unauthenticated attackers to inject arbitrary PHP objects into the application, potentially leading to remote code execution, unauthorized data access, or complete site compromise. The vulnerability exists in WPFunnels versions through 3.5.18.

Critical Impact

Unauthenticated attackers can exploit this PHP Object Injection vulnerability to execute arbitrary code, manipulate data, or gain full control over affected WordPress installations without any user interaction required.

Affected Products

• WPFunnels WordPress Plugin versions n/a through 3.5.18

Discovery Timeline

• May 23, 2025 - CVE-2025-47530 published to NVD
• May 23, 2025 - Last updated in NVD database

Technical Details for CVE-2025-47530

Vulnerability Analysis

This vulnerability falls under CWE-502 (Deserialization of Untrusted Data), a well-documented class of security flaws that can have severe consequences in PHP applications. The WPFunnels plugin fails to properly validate or sanitize serialized data before passing it to PHP's unserialize() function, creating an Object Injection attack surface.

When a PHP application deserializes untrusted input, an attacker can craft malicious serialized objects that, when instantiated, trigger dangerous operations through magic methods such as __wakeup(), __destruct(), or __toString(). In WordPress environments, the presence of numerous plugins and themes creates a rich landscape of potential "gadget chains" that attackers can leverage to achieve code execution.

The network-accessible nature of this vulnerability combined with no authentication requirements makes it particularly dangerous for internet-facing WordPress sites using WPFunnels.

Root Cause

The root cause of this vulnerability is the insecure handling of serialized PHP data within the WPFunnels plugin. The application accepts user-controlled serialized input and passes it directly to the unserialize() function without proper validation, type checking, or use of allowed class restrictions.

PHP's native unserialize() function will instantiate any object represented in the serialized string, executing magic methods automatically. Without restricting which classes can be deserialized or implementing signature verification on serialized payloads, the plugin creates a direct path for object injection attacks.

Attack Vector

The attack is network-based and requires no authentication or user interaction. An attacker can exploit this vulnerability by:

1. Identifying an endpoint in WPFunnels that processes serialized data
2. Crafting a malicious serialized PHP object payload containing a gadget chain
3. Sending the payload to the vulnerable endpoint
4. The server deserializes the object, triggering the gadget chain and executing attacker-controlled operations

The vulnerability is particularly severe because attackers can leverage existing PHP classes within WordPress core, WPFunnels itself, or other installed plugins to construct Property Oriented Programming (POP) chains that achieve code execution.

For technical details on the specific vulnerable code paths, see the Patchstack security advisory.

Detection Methods for CVE-2025-47530

Indicators of Compromise

• Unusual HTTP requests containing serialized PHP data (strings starting with O:, a:, or s: patterns) targeting WPFunnels endpoints
• Unexpected file creation or modification in WordPress directories, particularly in wp-content/uploads/ or plugin directories
• Anomalous outbound network connections from the web server process
• New or modified WordPress user accounts, especially administrator accounts

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in request parameters
• Monitor WordPress audit logs for unauthorized administrative actions or plugin modifications
• Deploy file integrity monitoring on the WordPress installation to detect unauthorized file changes
• Review web server access logs for suspicious POST requests to WPFunnels-related endpoints

Monitoring Recommendations

• Enable detailed logging for all HTTP requests processed by the WordPress installation
• Configure alerts for any modifications to critical WordPress files or database tables
• Monitor for PHP errors or warnings related to unserialization failures, which may indicate exploitation attempts
• Implement network monitoring to detect unusual outbound connections from the web server

How to Mitigate CVE-2025-47530

Immediate Actions Required

• Update WPFunnels to a patched version beyond 3.5.18 immediately
• If an update is not available, temporarily disable the WPFunnels plugin until a patch is released
• Review WordPress audit logs and server access logs for signs of exploitation
• Conduct a security assessment of the WordPress installation to identify any potential compromise

Patch Information

Organizations using WPFunnels should check for updates through the WordPress plugin repository or the vendor's official channels. The vulnerability affects all versions through 3.5.18, so updating to any version that specifically addresses CVE-2025-47530 is essential.

For detailed vulnerability information and patch status, refer to the Patchstack WPFunnels Vulnerability advisory.

Workarounds

• Disable the WPFunnels plugin entirely until an official patch is available
• Implement WAF rules to block requests containing serialized PHP object patterns targeting the WordPress installation
• Restrict access to the WordPress admin and plugin endpoints using IP allowlisting where feasible
• Consider using a virtual patching solution that can filter malicious serialized payloads at the network level

# Example WAF rule pattern to detect serialized PHP objects
# Add to .htaccess or WAF configuration
# Block requests containing PHP serialized object patterns
# Note: Adjust based on your specific WAF platform
RewriteEngine On
RewriteCond %{QUERY_STRING} (O:\d+:"|a:\d+:{|s:\d+:") [NC,OR]
RewriteCond %{REQUEST_BODY} (O:\d+:"|a:\d+:{|s:\d+:") [NC]
RewriteRule .* - [F,L]