CVE-2025-58636: WP Gravity Forms Keap Object Injection

CVE-2025-58636 Overview

A critical Deserialization of Untrusted Data vulnerability has been identified in the CRM Perks WP Gravity Forms Keap/Infusionsoft plugin (gf-infusionsoft). This vulnerability allows attackers to perform Object Injection attacks against WordPress installations running vulnerable versions of the plugin. The flaw stems from improper handling of serialized data, enabling malicious actors to inject arbitrary PHP objects that could lead to remote code execution, data theft, or complete site compromise.

Critical Impact

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

Affected Products

• WP Gravity Forms Keap/Infusionsoft plugin version 1.2.3 and earlier
• WordPress installations with the gf-infusionsoft plugin enabled
• Sites integrating Gravity Forms with Keap/Infusionsoft CRM services

Discovery Timeline

• 2025-11-06 - CVE-2025-58636 published to NVD
• 2026-01-20 - Last updated in NVD database

Technical Details for CVE-2025-58636

Vulnerability Analysis

This vulnerability falls under CWE-502 (Deserialization of Untrusted Data), a dangerous class of security flaws that occurs when applications deserialize data from untrusted sources without proper validation. In PHP applications like WordPress plugins, insecure deserialization typically involves the unserialize() function processing user-controlled input.

The WP Gravity Forms Keap/Infusionsoft plugin fails to adequately sanitize or validate serialized data before processing it, allowing attackers to craft malicious serialized payloads. When these payloads are deserialized, they can instantiate arbitrary PHP objects with attacker-controlled properties. Combined with existing PHP classes containing exploitable "magic methods" (such as __wakeup(), __destruct(), or __toString()), this can lead to a complete Property-Oriented Programming (POP) chain attack.

Root Cause

The root cause of this vulnerability is the unsafe deserialization of user-supplied data within the gf-infusionsoft plugin. The plugin processes serialized input without implementing adequate security controls such as:

• Input validation before deserialization
• Whitelist-based class restrictions
• Signature verification of serialized data
• Use of safer alternatives like JSON encoding

This architectural weakness allows any network-accessible attacker to submit crafted serialized payloads that the application will blindly process.

Attack Vector

The vulnerability is exploitable over the network without authentication or user interaction. An attacker can submit a specially crafted HTTP request containing a malicious serialized PHP object to the vulnerable endpoint. The attack flow typically involves:

1. Identifying a vulnerable WordPress installation running WP Gravity Forms Keap/Infusionsoft version 1.2.3 or earlier
2. Crafting a malicious serialized PHP payload targeting available POP gadget chains
3. Submitting the payload via the vulnerable input vector
4. The plugin deserializes the untrusted data, instantiating the attacker's objects
5. Magic methods in the instantiated objects execute, leading to code execution or other malicious outcomes

The vulnerability allows Object Injection attacks where attackers can instantiate arbitrary PHP classes with controlled property values. When combined with suitable gadget chains available in WordPress core, popular plugins, or the target application itself, this can escalate to remote code execution. For detailed technical analysis, see the PatchStack Vulnerability Report.

Detection Methods for CVE-2025-58636

Indicators of Compromise

• Unexpected serialized data patterns in HTTP request logs, particularly containing class instantiation syntax like O: followed by class names
• Unusual PHP object instantiation errors in WordPress debug logs
• Suspicious POST requests targeting plugin endpoints with serialized payloads
• Evidence of unexpected file creation or modification in WordPress directories
• Anomalous database queries or unauthorized administrative actions

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in incoming requests
• Monitor HTTP traffic for payloads containing PHP serialization markers such as O:, a:, s: followed by suspicious class names
• Implement file integrity monitoring to detect unauthorized modifications to WordPress core files, themes, and plugins
• Review access logs for unusual request patterns targeting the gf-infusionsoft plugin endpoints

Monitoring Recommendations

• Enable comprehensive WordPress logging including plugin activity and error logging
• Configure SIEM alerts for PHP deserialization attack signatures
• Implement real-time monitoring of web server access logs with pattern matching for serialized object injection attempts
• Deploy endpoint detection and response (EDR) solutions to identify post-exploitation activities

How to Mitigate CVE-2025-58636

Immediate Actions Required

• Immediately audit your WordPress installations to identify any instances running WP Gravity Forms Keap/Infusionsoft version 1.2.3 or earlier
• Disable the gf-infusionsoft plugin until a patched version is available and verified
• Implement WAF rules to block requests containing potentially malicious serialized PHP objects
• Review server logs for evidence of exploitation attempts
• Consider temporary network-level access restrictions to administrative endpoints

Patch Information

Organizations should monitor the official CRM Perks plugin repository and the PatchStack security advisory for updates regarding a security patch. Update to a version higher than 1.2.3 once a patched release becomes available. Always verify plugin updates through official WordPress.org channels or the vendor's authenticated distribution platform.

Workarounds

• Temporarily deactivate and remove the WP Gravity Forms Keap/Infusionsoft plugin until a patched version is released
• Deploy a Web Application Firewall with deserialization attack detection capabilities
• Restrict network access to WordPress administrative interfaces using IP whitelisting
• Consider alternative CRM integration solutions that do not have known vulnerabilities
• Implement PHP disable_functions directive to restrict dangerous functions that could be leveraged in POP chain attacks

# WordPress plugin deactivation via WP-CLI
wp plugin deactivate gf-infusionsoft --path=/var/www/html/wordpress

# Verify plugin status
wp plugin list --path=/var/www/html/wordpress | grep gf-infusionsoft