CVE-2025-60174: WP Gravity Forms Constant Contact Plugin

CVE-2025-60174 Overview

CVE-2025-60174 is a critical insecure deserialization vulnerability affecting the WP Gravity Forms Constant Contact Plugin developed by CRM Perks. This WordPress plugin, which provides integration between Gravity Forms and Constant Contact email marketing services, contains a flaw that allows attackers to perform Object Injection attacks through deserialization of untrusted data. The vulnerability can be exploited remotely without authentication, potentially leading to complete compromise of the affected WordPress installation.

Critical Impact

Unauthenticated attackers can exploit this deserialization vulnerability to inject malicious objects, potentially achieving remote code execution, data theft, or complete site takeover on WordPress installations using the affected plugin.

Affected Products

• CRM Perks WP Gravity Forms Constant Contact Plugin versions through 1.1.2
• WordPress installations with gf-constant-contact plugin installed
• Sites using Gravity Forms integration with Constant Contact

Discovery Timeline

• 2025-12-18 - CVE-2025-60174 published to NVD
• 2026-01-20 - Last updated in NVD database

Technical Details for CVE-2025-60174

Vulnerability Analysis

This vulnerability stems from the unsafe handling of serialized data within the WP Gravity Forms Constant Contact Plugin. PHP's unserialize() function, when used without proper validation, can instantiate arbitrary objects from attacker-controlled input. In the context of WordPress, this creates a particularly dangerous attack surface due to the rich ecosystem of classes available from the core, themes, and other plugins that may contain exploitable magic methods.

The deserialization vulnerability (CWE-502) enables attackers to construct malicious serialized payloads that, when processed by the plugin, instantiate objects with attacker-controlled properties. These objects can then trigger dangerous operations through PHP magic methods such as __wakeup(), __destruct(), or __toString(). The attack does not require any user interaction or authentication, making it highly exploitable across the network.

Successful exploitation can result in unauthorized access to the WordPress database, execution of arbitrary PHP code on the server, modification or deletion of site content, and lateral movement within the hosting environment.

Root Cause

The root cause of CVE-2025-60174 is the use of PHP's native deserialization functions on user-controllable input without adequate validation or sanitization. The plugin fails to implement proper input filtering before deserializing data, allowing attackers to inject crafted serialized strings containing malicious object references. This represents a fundamental security oversight in how external data is processed by the plugin.

Attack Vector

The attack vector is network-based, requiring no authentication or user interaction. An attacker can craft a malicious HTTP request containing a specially constructed serialized PHP object payload. When the vulnerable plugin processes this request and deserializes the attacker-controlled data, it triggers the instantiation of arbitrary PHP objects.

The attacker leverages existing PHP classes present in the WordPress ecosystem (known as "gadget chains") to chain together method calls that ultimately achieve code execution or other malicious outcomes. Common targets include file operations, database queries, or command execution functions accessible through the WordPress environment.

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

Detection Methods for CVE-2025-60174

Indicators of Compromise

• Unusual POST requests to WordPress endpoints associated with the gf-constant-contact plugin containing serialized PHP data
• Web server logs showing requests with base64-encoded or URL-encoded serialized object strings
• Unexpected file modifications or new files created in the WordPress installation directory
• Database entries containing serialized data with unexpected class references
• Anomalous outbound connections from the web server indicative of reverse shell activity

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in HTTP requests
• Monitor WordPress plugin directories for unauthorized file changes or new file creation
• Deploy endpoint detection solutions like SentinelOne to identify post-exploitation activities such as process spawning from web server contexts
• Review web server access logs for suspicious patterns targeting the gf-constant-contact plugin endpoints
• Utilize file integrity monitoring to detect changes to plugin files or WordPress core

Monitoring Recommendations

• Enable verbose logging for the WordPress installation and review for deserialization-related errors or warnings
• Configure alerts for any new PHP files created within the WordPress directory structure
• Monitor outbound network connections from the web server for potential command and control traffic
• Implement real-time alerting on WAF rule triggers related to serialization attack patterns

How to Mitigate CVE-2025-60174

Immediate Actions Required

• Immediately disable or remove the WP Gravity Forms Constant Contact Plugin (gf-constant-contact) if running version 1.1.2 or earlier
• Review WordPress installation for signs of compromise including unexpected files, modified content, or new administrator accounts
• Check for and update to a patched version of the plugin if one becomes available from CRM Perks
• Conduct a security audit of the WordPress installation to identify any exploitation artifacts

Patch Information

At the time of this analysis, organizations should monitor for updates from CRM Perks for the WP Gravity Forms Constant Contact Plugin. The vulnerability affects all versions through 1.1.2. Administrators should check the WordPress plugin repository and the vendor's website for security advisories and updated releases. Additional details can be found in the Patchstack Vulnerability Report.

Workarounds

• Deactivate and remove the vulnerable plugin until a patched version is available
• Implement WAF rules to block requests containing serialized PHP object signatures targeting the plugin
• Restrict access to WordPress administrative areas using IP allowlisting or VPN requirements
• Consider using an alternative Gravity Forms to Constant Contact integration solution that does not have this vulnerability

# Configuration example
# Disable the vulnerable plugin via WP-CLI
wp plugin deactivate gf-constant-contact --path=/var/www/html/wordpress

# Alternatively, remove the plugin entirely
wp plugin delete gf-constant-contact --path=/var/www/html/wordpress

# Verify plugin is no longer active
wp plugin list --path=/var/www/html/wordpress | grep gf-constant-contact