CVE-2025-53572: WP Easy Contact Object Injection Flaw

CVE-2025-53572 Overview

CVE-2025-53572 is a deserialization of untrusted data vulnerability in the WP Easy Contact WordPress plugin by emarket-design. This PHP Object Injection vulnerability allows attackers to inject malicious serialized objects into the application, potentially leading to remote code execution, data manipulation, or unauthorized access to the underlying system.

Critical Impact

Unauthenticated attackers may exploit insecure deserialization to achieve arbitrary code execution, compromise sensitive data, or gain unauthorized control over WordPress installations running vulnerable versions of WP Easy Contact.

Affected Products

• WP Easy Contact plugin versions up to and including 4.0.1
• WordPress installations utilizing the vulnerable wp-easy-contact plugin
• Websites with publicly accessible WP Easy Contact forms or endpoints

Discovery Timeline

• 2025-08-28 - CVE-2025-53572 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-53572

Vulnerability Analysis

This vulnerability stems from improper handling of serialized data within the WP Easy Contact plugin. PHP's unserialize() function, when processing user-controlled input without proper validation, can instantiate arbitrary objects and trigger their magic methods such as __wakeup() or __destruct(). When a suitable "gadget chain" exists within the WordPress installation or its plugins, attackers can leverage these magic methods to execute arbitrary PHP code, access files, or perform other malicious actions.

The network-based attack vector means this vulnerability can be exploited remotely without requiring any authentication. However, successful exploitation requires the attacker to identify and chain compatible PHP classes (gadgets) present on the target system, which adds complexity to the attack. The impact upon successful exploitation is severe, potentially compromising confidentiality, integrity, and availability of the affected WordPress installation.

Root Cause

The root cause of CVE-2025-53572 is classified under CWE-502 (Deserialization of Untrusted Data). The WP Easy Contact plugin fails to properly sanitize or validate serialized input before passing it to PHP's native deserialization functions. This allows user-supplied serialized payloads to be processed by the server, enabling attackers to instantiate arbitrary objects within the application context. The absence of input validation and secure deserialization practices creates the conditions necessary for object injection attacks.

Attack Vector

The attack is executed over the network without requiring prior authentication. An attacker crafts a malicious serialized PHP object payload targeting known gadget chains available in the WordPress ecosystem. This payload is then submitted to a vulnerable endpoint within the WP Easy Contact plugin. When the server deserializes the payload, the injected object's magic methods are triggered, executing the attacker's intended operations.

The exploitation process typically involves:

1. Identifying a vulnerable WP Easy Contact installation running version 4.0.1 or earlier
2. Discovering available PHP classes (gadgets) on the target that can be chained for malicious purposes
3. Crafting a serialized payload that leverages these gadgets to achieve code execution or other objectives
4. Submitting the payload to the vulnerable deserialization endpoint
5. The server processes the payload, triggering the attack chain

For detailed technical information about this vulnerability, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2025-53572

Indicators of Compromise

• Unusual POST requests to WP Easy Contact plugin endpoints containing serialized PHP data patterns (e.g., O: followed by class names)
• Web server logs showing requests with encoded or obfuscated serialized object payloads
• Unexpected file modifications or new files created in WordPress directories
• Anomalous PHP process execution or system command invocations originating from WordPress
• Database modifications inconsistent with normal plugin operations

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in request parameters
• Monitor access logs for suspicious requests targeting /wp-content/plugins/wp-easy-contact/ paths with unusual payload sizes
• Deploy endpoint detection solutions to identify unexpected PHP process behaviors or shell spawning
• Utilize file integrity monitoring to detect unauthorized changes to WordPress core and plugin files
• Implement intrusion detection rules for known PHP object injection payload signatures

Monitoring Recommendations

• Enable verbose logging for the WP Easy Contact plugin and review logs for deserialization-related errors
• Configure real-time alerting for POST requests containing serialized data patterns to WordPress plugin endpoints
• Monitor system processes for unexpected child processes spawned by PHP workers
• Review database activity for unusual INSERT or UPDATE operations against WordPress tables
• Implement network traffic analysis to detect outbound connections initiated by the web server

How to Mitigate CVE-2025-53572

Immediate Actions Required

• Audit your WordPress installations to identify any instances of WP Easy Contact plugin version 4.0.1 or earlier
• If a patched version is available from the vendor, update immediately to the latest secure release
• Consider temporarily deactivating and removing the WP Easy Contact plugin if no patch is available
• Implement WAF rules to block requests containing PHP serialized object patterns
• Review server logs for any evidence of exploitation attempts

Patch Information

Organizations should consult the Patchstack Vulnerability Report for the latest information on available patches and remediation guidance from the plugin developer. Ensure that any updates are obtained from official WordPress plugin repository or the vendor's trusted distribution channels.

Workarounds

• Disable the WP Easy Contact plugin until a security patch is released and applied
• Implement strict input validation at the web server or WAF level to reject serialized PHP data in requests
• Restrict access to WordPress admin and plugin endpoints using IP allowlisting where feasible
• Deploy a PHP security extension such as Snuffleupagus or Suhosin to restrict deserialization capabilities
• Consider migrating to an alternative contact form plugin with a stronger security track record

# Example: Disable WP Easy Contact plugin via WP-CLI
wp plugin deactivate wp-easy-contact --path=/var/www/html/wordpress

# Example: ModSecurity rule to block PHP serialized objects
SecRule REQUEST_BODY "@rx O:\d+:\"[^\"]+\":\d+:{" \
    "id:100001,phase:2,deny,status:403,msg:'PHP Object Injection Attempt Blocked'"