CVE-2026-25316: CartFlows Object Injection Vulnerability

CVE-2026-25316 Overview

CVE-2026-25316 is a Deserialization of Untrusted Data vulnerability affecting the Brainstorm Force CartFlows plugin for WordPress. This security flaw enables attackers to perform PHP Object Injection attacks against vulnerable installations. The vulnerability exists in CartFlows versions up to and including 2.1.19, allowing malicious actors to inject arbitrary PHP objects into the application through unsafe deserialization of user-controlled data.

Critical Impact

Successful exploitation of this PHP Object Injection vulnerability could allow attackers to execute arbitrary code, manipulate application logic, or compromise the underlying WordPress installation depending on available gadget chains.

Affected Products

• Brainstorm Force CartFlows WordPress Plugin versions through 2.1.19
• WordPress installations running vulnerable CartFlows versions

Discovery Timeline

• 2026-02-19 - CVE CVE-2026-25316 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-25316

Vulnerability Analysis

This vulnerability stems from improper handling of serialized data within the CartFlows WordPress plugin. PHP Object Injection vulnerabilities occur when user-supplied input is passed to PHP's unserialize() function without proper validation or sanitization. When exploited, this allows an attacker to instantiate arbitrary PHP objects, which can lead to various security impacts depending on the classes available within the application and its dependencies.

The severity of PHP Object Injection attacks depends significantly on the "gadget chains" available in the codebase. In WordPress environments, numerous plugins and themes may introduce exploitable classes that could be leveraged to achieve remote code execution, file deletion, privilege escalation, or other malicious outcomes.

Root Cause

The root cause of CVE-2026-25316 is classified under CWE-502 (Deserialization of Untrusted Data). The CartFlows plugin fails to properly validate or sanitize serialized data before processing it through PHP's deserialization functions. This design flaw violates the security principle that untrusted data should never be deserialized without strict controls.

In PHP applications, the unserialize() function reconstructs objects from their serialized string representation. When this function processes attacker-controlled input, magic methods such as __wakeup(), __destruct(), or __toString() can be triggered on instantiated objects, potentially leading to code execution or other unintended behaviors.

Attack Vector

The attack vector for this vulnerability involves an attacker crafting a malicious serialized PHP object payload and submitting it to a vulnerable endpoint within the CartFlows plugin. The exact entry point would depend on how the plugin processes user input, but common vectors include form submissions, AJAX requests, or URL parameters that accept serialized data.

An attacker would typically:

1. Identify available PHP classes within the WordPress installation that contain exploitable magic methods
2. Construct a serialized object payload that chains together these classes to achieve the desired malicious outcome
3. Submit the crafted payload to the vulnerable CartFlows endpoint
4. Upon deserialization, the payload triggers the gadget chain, executing the attacker's intended actions

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

Detection Methods for CVE-2026-25316

Indicators of Compromise

• Unusual serialized data patterns in web server access logs, particularly containing PHP object notation (e.g., O:, a:, s: prefixes)
• Unexpected file system modifications or new files created by the web server process
• Anomalous database queries or modifications not associated with normal plugin operation
• Error logs showing PHP object instantiation failures or unexpected class loading

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block serialized PHP object patterns in request parameters
• Monitor WordPress plugin directories for unauthorized file changes or new file creation
• Deploy runtime application security monitoring to detect unexpected object instantiation
• Enable verbose logging for the CartFlows plugin and review for suspicious deserialization activity

Monitoring Recommendations

• Audit web server logs for requests containing serialized data patterns targeting CartFlows endpoints
• Implement file integrity monitoring on WordPress installation directories
• Configure alerts for suspicious PHP process behavior including unexpected network connections or file operations
• Review authentication logs for signs of privilege escalation following exploitation attempts

How to Mitigate CVE-2026-25316

Immediate Actions Required

• Update the CartFlows plugin to a version newer than 2.1.19 that addresses this vulnerability
• Audit your WordPress installation for signs of compromise if the vulnerable version was deployed
• Review and remove any unknown or suspicious files from the WordPress installation
• Consider temporarily disabling the CartFlows plugin until a patched version can be applied

Patch Information

Users should update the CartFlows WordPress plugin to the latest available version that addresses this PHP Object Injection vulnerability. Consult the Patchstack Vulnerability Report for specific patch details and remediation guidance.

Workarounds

• Deploy a Web Application Firewall (WAF) with rules to detect and block PHP serialized object patterns
• Implement input validation at the server level to reject requests containing serialized PHP data where not explicitly required
• Restrict access to WordPress administrative endpoints using IP allowlisting or VPN requirements
• Enable WordPress security plugins that provide runtime protection against object injection attacks

# Configuration example - WordPress .htaccess rule to block suspicious serialized data patterns
# Add to .htaccess in WordPress root directory
<IfModule mod_rewrite.c>
    RewriteEngine On
    # Block requests containing PHP serialized object patterns
    RewriteCond %{QUERY_STRING} (O:\d+:\"[a-zA-Z_]+\") [NC,OR]
    RewriteCond %{REQUEST_BODY} (O:\d+:\"[a-zA-Z_]+\") [NC]
    RewriteRule .* - [F,L]
</IfModule>