CVE-2026-0910: wpForo Forum Plugin RCE Vulnerability

CVE-2026-0910 Overview

The wpForo Forum plugin for WordPress contains a PHP Object Injection vulnerability affecting all versions up to and including 2.4.13. The vulnerability exists due to unsafe deserialization of untrusted input in the wpforo_display_array_data function. Authenticated attackers with Subscriber-level access or higher can exploit this flaw to inject malicious PHP objects into the application.

While no known POP (Property Oriented Programming) chain is present in the vulnerable wpForo plugin itself, the vulnerability becomes significantly more dangerous when combined with other WordPress plugins or themes that contain exploitable POP chains. If such a chain exists on the target system, attackers may be able to delete arbitrary files, retrieve sensitive data, or achieve remote code execution.

Critical Impact

Authenticated attackers can inject PHP objects that, when combined with POP chains from other installed plugins or themes, may lead to arbitrary file deletion, sensitive data exposure, or remote code execution.

Affected Products

• wpForo Forum plugin for WordPress versions up to and including 2.4.13
• WordPress installations with wpForo Forum and additional plugins/themes containing POP chains

Discovery Timeline

• 2026-02-11 - CVE-2026-0910 published to NVD
• 2026-02-11 - Last updated in NVD database

Technical Details for CVE-2026-0910

Vulnerability Analysis

This vulnerability is classified as CWE-502 (Deserialization of Untrusted Data). The wpForo Forum plugin improperly handles user-controlled data by passing it through PHP's deserialization functionality without adequate validation or sanitization. The vulnerable code resides in the debug.php file within the admin tools section of the plugin.

PHP Object Injection vulnerabilities occur when an application deserializes user-supplied data without proper validation. During the deserialization process, PHP automatically invokes magic methods such as __wakeup(), __destruct(), or __toString() on the reconstructed objects. Attackers can craft serialized payloads that, when deserialized, instantiate objects with attacker-controlled properties, potentially triggering dangerous operations through these magic methods.

The exploitation requires authentication with at least Subscriber-level privileges, which lowers the barrier to attack since many WordPress sites allow user registration. The network-accessible nature of WordPress installations makes this vulnerability remotely exploitable without user interaction.

Root Cause

The root cause lies in the wpforo_display_array_data function located in /admin/tools-tabs/debug.php. This function processes data without validating whether it contains serialized PHP objects, allowing attackers to inject malicious serialized payloads. The function fails to implement safe deserialization practices such as using JSON encoding/decoding or restricting allowed classes during unserialization.

Attack Vector

The attack is conducted over the network and requires the attacker to have authenticated access to the WordPress site with at least Subscriber-level privileges. The attacker crafts a malicious serialized PHP object payload and submits it through a mechanism that triggers the vulnerable wpforo_display_array_data function.

The exploitation flow typically involves:

1. The attacker registers or compromises a Subscriber-level account on the target WordPress site
2. The attacker identifies plugins or themes on the target that contain exploitable POP chains
3. The attacker crafts a serialized payload targeting the identified POP chain
4. The payload is submitted through a request that invokes the vulnerable function
5. Upon deserialization, the injected object triggers the POP chain, executing malicious operations

For technical details on the vulnerable code, refer to the WordPress Debug File and the WordPress Changeset Update showing the patch.

Detection Methods for CVE-2026-0910

Indicators of Compromise

• Unusual serialized data patterns in web server logs containing PHP object notation (e.g., O: followed by class names)
• Unexpected file deletions or modifications in WordPress directories
• Suspicious database queries or data exfiltration attempts originating from wpForo-related requests
• Error logs showing PHP unserialization warnings or exceptions

Detection Strategies

• Monitor HTTP request bodies for serialized PHP object patterns targeting wpForo endpoints
• Implement Web Application Firewall (WAF) rules to detect and block serialized PHP object injection attempts
• Enable WordPress debug logging to capture deserialization-related errors
• Review access logs for suspicious activity from Subscriber-level accounts accessing admin tool endpoints

Monitoring Recommendations

• Audit all installed plugins and themes for known POP chains that could be exploited in combination with this vulnerability
• Monitor file integrity on the WordPress installation to detect unauthorized modifications
• Track authentication events and unusual activity from low-privilege accounts
• Implement logging for the wpforo_display_array_data function calls to identify exploitation attempts

How to Mitigate CVE-2026-0910

Immediate Actions Required

• Update wpForo Forum plugin to version 2.4.14 or later immediately
• Audit WordPress user accounts and remove unnecessary Subscriber-level or higher accounts
• Review installed plugins and themes for known POP chain vulnerabilities
• Consider temporarily disabling the wpForo Forum plugin if immediate patching is not possible

Patch Information

The vulnerability has been addressed in wpForo Forum version 2.4.14. The patch modifies the debug.php file to properly sanitize and validate input before processing. Site administrators should update through the WordPress plugin update mechanism or download the patched version from the official WordPress plugin repository. The specific code changes can be reviewed in the WordPress Changeset Update.

Workarounds

• Restrict user registration to prevent unauthorized Subscriber account creation
• Implement WAF rules to block requests containing serialized PHP objects
• Remove or disable unnecessary plugins and themes that may contain POP chains
• Restrict access to WordPress admin and debug functionality at the server level

# Example .htaccess rule to restrict access to wpForo debug tools
<FilesMatch "debug\.php$">
    Order Deny,Allow
    Deny from all
    Allow from 127.0.0.1
</FilesMatch>