CVE-2025-30985: GNUCommerce Deserialization Vulnerability

CVE-2025-30985 Overview

A critical PHP Object Injection vulnerability has been identified in the GNUCommerce WordPress plugin. This vulnerability stems from insecure deserialization of untrusted data, allowing attackers to inject malicious objects that can lead to remote code execution, data theft, or complete site compromise.

Critical Impact

Unauthenticated attackers can exploit this PHP Object Injection vulnerability to execute arbitrary code, compromise sensitive data, and potentially gain full control of affected WordPress installations running GNUCommerce plugin versions 1.5.4 and earlier.

Affected Products

• GNUCommerce WordPress Plugin through version 1.5.4
• WordPress installations with vulnerable GNUCommerce plugin active
• All sites using unpatched versions of the plugin

Discovery Timeline

• April 15, 2025 - CVE-2025-30985 published to NVD
• April 15, 2025 - Last updated in NVD database

Technical Details for CVE-2025-30985

Vulnerability Analysis

This vulnerability is classified under CWE-502 (Deserialization of Untrusted Data), a well-known weakness that occurs when an application deserializes data from untrusted sources without proper validation. In the context of PHP applications like WordPress plugins, this manifests as PHP Object Injection.

When user-controlled serialized data is passed to PHP's unserialize() function without adequate sanitization, an attacker can craft malicious serialized objects. These objects can trigger "magic methods" such as __wakeup(), __destruct(), or __toString() when deserialized, leading to unintended code execution. The attack surface becomes particularly dangerous when the application or its dependencies contain classes with exploitable magic methods, commonly referred to as "gadget chains."

Root Cause

The root cause of CVE-2025-30985 lies in the GNUCommerce plugin's improper handling of serialized data. The plugin accepts user-supplied serialized input and processes it using PHP's native deserialization functions without implementing proper validation, sanitization, or allowlist controls for expected object types.

PHP's unserialize() function reconstructs objects from their serialized string representation. When an attacker can control this input, they can instantiate arbitrary classes and manipulate object properties, which can be chained to achieve remote code execution depending on available gadgets in the WordPress ecosystem.

Attack Vector

The attack can be executed remotely over the network without requiring authentication or user interaction. An attacker crafts a malicious serialized PHP object payload and submits it to a vulnerable endpoint in the GNUCommerce plugin.

The exploitation flow typically involves:

1. Identifying a vulnerable deserialization entry point in the GNUCommerce plugin
2. Analyzing available classes in WordPress core, the plugin itself, or other installed plugins/themes for exploitable magic methods
3. Constructing a Property Oriented Programming (POP) chain using these classes
4. Serializing the malicious object and submitting it to the vulnerable endpoint
5. Upon deserialization, the POP chain executes, potentially achieving remote code execution

For detailed technical analysis, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-30985

Indicators of Compromise

• Unexpected serialized data in HTTP request parameters, cookies, or POST bodies containing class names like O: followed by unusual class references
• Suspicious PHP error logs indicating failed object instantiation or unexpected class loading
• Unusual outbound network connections from the web server process
• Newly created or modified PHP files in WordPress directories
• Unexpected cron jobs or scheduled tasks on the server

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block serialized PHP objects in user input (patterns matching O:[0-9]+:)
• Implement file integrity monitoring on WordPress plugin directories to detect unauthorized modifications
• Configure PHP to log deserialization warnings and monitor for anomalies
• Review web server access logs for requests to GNUCommerce plugin endpoints with suspicious payloads

Monitoring Recommendations

• Enable comprehensive logging for WordPress and the GNUCommerce plugin
• Set up real-time alerting for file system changes within the wp-content/plugins/gnucommerce/ directory
• Monitor for unusual process spawning from PHP-FPM or Apache/Nginx worker processes
• Track failed authentication attempts and unusual administrative actions following plugin access

How to Mitigate CVE-2025-30985

Immediate Actions Required

• Immediately disable the GNUCommerce plugin if it is not essential for site operations
• Audit your WordPress installation for signs of compromise
• Review server logs for any suspicious activity related to the plugin
• Consider implementing a WAF rule to block serialized object patterns in requests to the plugin

Patch Information

At the time of publication, users should check the official WordPress plugin repository and the Patchstack vulnerability database for updated versions of the GNUCommerce plugin that address this vulnerability. If no patch is available, consider removing the plugin entirely and seeking alternative solutions.

Workarounds

• Deactivate and remove the GNUCommerce plugin until a patched version is available
• Implement WAF rules to filter serialized PHP object patterns in incoming requests
• Restrict access to WordPress admin and plugin functionality to trusted IP addresses only
• Apply the principle of least privilege to WordPress database users and file system permissions
• Consider using WordPress security plugins that provide object injection protection

# Configuration example - WAF rule for ModSecurity to block PHP serialized objects
SecRule REQUEST_BODY|REQUEST_URI|ARGS "@rx O:[0-9]+:\"[a-zA-Z_]" \
    "id:1001,\
    phase:2,\
    deny,\
    status:403,\
    log,\
    msg:'Potential PHP Object Injection Attempt Blocked'"