CVE-2025-24601: FundPress Object Injection Vulnerability

CVE-2025-24601 Overview

CVE-2025-24601 is a critical deserialization of untrusted data vulnerability affecting the ThimPress FundPress WordPress plugin. This vulnerability allows attackers to perform PHP Object Injection attacks, potentially leading to remote code execution, data manipulation, or complete site compromise. The vulnerability exists in FundPress versions up to and including 2.0.6.

Critical Impact

Unauthenticated attackers can exploit this PHP Object Injection vulnerability to execute arbitrary code, access sensitive data, or fully compromise WordPress installations running vulnerable versions of FundPress.

Affected Products

• ThimPress FundPress plugin versions through 2.0.6
• WordPress installations using the FundPress plugin

Discovery Timeline

• 2025-01-27 - CVE-2025-24601 published to NVD
• 2025-01-27 - Last updated in NVD database

Technical Details for CVE-2025-24601

Vulnerability Analysis

This vulnerability is classified as CWE-502 (Deserialization of Untrusted Data). The FundPress plugin fails to properly validate and sanitize serialized data before passing it to PHP's unserialize() function. When untrusted data is deserialized without adequate validation, attackers can craft malicious serialized payloads that, when processed, instantiate arbitrary objects with attacker-controlled properties.

The network-accessible nature of this vulnerability means that attackers can exploit it remotely without requiring any prior authentication or user interaction. Once a malicious payload is deserialized, attackers can leverage existing PHP gadget chains within WordPress or installed plugins to achieve arbitrary code execution, file manipulation, or database access.

Root Cause

The root cause of this vulnerability lies in the improper handling of serialized PHP data within the FundPress plugin. The plugin accepts user-controlled input containing serialized data and passes it directly to PHP's unserialize() function without proper validation or sanitization. This allows attackers to inject malicious serialized objects that execute arbitrary operations when reconstructed by PHP.

Attack Vector

The attack vector for CVE-2025-24601 is network-based, requiring no authentication or user interaction. An attacker can submit a crafted HTTP request containing a malicious serialized PHP object to the vulnerable endpoint. When the FundPress plugin deserializes this payload, it instantiates the attacker's chosen object with controlled property values. If a suitable "gadget chain" exists in the WordPress environment—a sequence of class methods that can be chained together during object destruction or wake-up—the attacker can achieve remote code execution or other malicious outcomes.

The exploitation typically involves:

1. Identifying the vulnerable deserialization point in FundPress
2. Crafting a serialized payload containing malicious PHP objects
3. Submitting the payload via an HTTP request to the vulnerable endpoint
4. The plugin deserializes the payload, triggering the gadget chain
5. Arbitrary code execution or other malicious actions occur

For detailed technical information about this vulnerability, see the Patchstack security advisory.

Detection Methods for CVE-2025-24601

Indicators of Compromise

• Unusual HTTP requests containing serialized PHP data (strings starting with O: or a:) to FundPress endpoints
• Unexpected file modifications or new files in WordPress directories
• Suspicious PHP processes or outbound network connections from the web server
• Database entries with serialized object notation that appear malformed or contain unexpected class names

Detection Strategies

• Monitor web application firewall (WAF) logs for requests containing serialized PHP payloads
• Implement file integrity monitoring on WordPress installations to detect unauthorized changes
• Review access logs for unusual POST requests targeting FundPress plugin endpoints
• Deploy runtime application self-protection (RASP) solutions to detect deserialization attacks

Monitoring Recommendations

• Enable verbose logging for WordPress and PHP to capture detailed request information
• Configure alerting for any detection of serialized PHP objects in HTTP request parameters
• Implement network monitoring to detect unexpected outbound connections from web servers
• Regularly audit WordPress plugin directories for unauthorized file additions or modifications

How to Mitigate CVE-2025-24601

Immediate Actions Required

• Update FundPress plugin to a patched version as soon as one becomes available
• If no patch is available, consider temporarily disabling the FundPress plugin until a fix is released
• Implement Web Application Firewall (WAF) rules to block requests containing serialized PHP objects
• Review server logs for any indicators of exploitation attempts or successful compromises
• Consider restricting access to the WordPress admin area and plugin endpoints via IP allowlisting

Patch Information

Organizations should monitor the Patchstack vulnerability database and the official ThimPress channels for patch announcements. Update to a version higher than 2.0.6 when available.

Workarounds

• Temporarily deactivate and remove the FundPress plugin if it is not critical to site operations
• Deploy a Web Application Firewall with rules to detect and block serialized PHP object payloads
• Implement input validation at the server level to reject requests containing suspicious serialized data
• Consider using WordPress security plugins that provide virtual patching capabilities for known vulnerabilities

# Example: Disable FundPress plugin via WP-CLI
wp plugin deactivate fundpress

# Verify plugin is deactivated
wp plugin list --status=inactive | grep fundpress