CVE-2025-22311: UserPro Private Messages RCE Vulnerability

CVE-2025-22311 Overview

CVE-2025-22311 is an Improper Control of Filename for Include/Require Statement in PHP Program vulnerability, commonly known as PHP Remote File Inclusion (RFI), affecting the Private Messages for UserPro WordPress plugin developed by DeluxeThemes. This vulnerability allows attackers to manipulate file inclusion parameters to potentially include malicious files from remote or local sources, leading to arbitrary code execution on vulnerable WordPress installations.

Critical Impact

This vulnerability enables attackers to exploit PHP's file inclusion mechanisms in the userpro-messaging plugin, potentially allowing remote code execution, sensitive data exposure, and complete WordPress site compromise through Local File Inclusion (LFI) attacks.

Affected Products

• Private Messages for UserPro WordPress Plugin version 4.10.0 and earlier
• WordPress installations running the userpro-messaging plugin
• All versions from initial release through version 4.10.0

Discovery Timeline

• 2025-01-21 - CVE-2025-22311 published to NVD
• 2026-04-23 - Last updated in NVD database

Technical Details for CVE-2025-22311

Vulnerability Analysis

This vulnerability falls under CWE-98 (Improper Control of Filename for Include/Require Statement in PHP Program). The Private Messages for UserPro plugin fails to properly validate and sanitize user-supplied input before using it in PHP file inclusion statements such as include(), include_once(), require(), or require_once(). This allows an attacker to manipulate the file path parameter to include arbitrary files, either from the local file system (Local File Inclusion) or potentially from remote sources (Remote File Inclusion).

The network-based attack vector requires user interaction, but no authentication is needed to exploit this vulnerability. A successful exploit can result in complete compromise of confidentiality, integrity, and availability of the affected WordPress installation.

Root Cause

The root cause of CVE-2025-22311 lies in insufficient input validation within the userpro-messaging plugin. The plugin accepts user-controlled input and passes it directly to PHP file inclusion functions without proper sanitization or whitelisting of allowed file paths. This allows attackers to traverse directories and include sensitive files such as wp-config.php or system files like /etc/passwd, or potentially execute PHP code from included files.

Attack Vector

The vulnerability is exploited through network-based requests where an attacker crafts malicious input targeting the file inclusion functionality of the userpro-messaging plugin. The attack requires some user interaction but does not require authentication, making it accessible to unauthenticated attackers.

Typical exploitation involves manipulating URL parameters or POST data to include arbitrary file paths using directory traversal sequences (e.g., ../) to access files outside the intended directory scope. Attackers may attempt to include configuration files to extract database credentials, include PHP wrapper streams to execute code, or leverage log file poisoning techniques for code execution.

Detection Methods for CVE-2025-22311

Indicators of Compromise

• Unusual HTTP requests containing directory traversal patterns (../) targeting the userpro-messaging plugin endpoints
• Access log entries showing attempts to include sensitive files like wp-config.php or /etc/passwd
• Unexpected PHP wrapper usage in request parameters (e.g., php://filter, data://)
• Web server error logs indicating failed file inclusion attempts or access to restricted directories

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block directory traversal patterns in requests to WordPress plugin endpoints
• Monitor WordPress access logs for suspicious requests containing file inclusion payloads targeting the userpro-messaging plugin
• Deploy file integrity monitoring on critical WordPress files to detect unauthorized modifications
• Use intrusion detection systems configured with signatures for LFI/RFI attack patterns

Monitoring Recommendations

• Enable detailed logging for the WordPress installation and review logs for anomalous plugin activity
• Set up alerts for requests containing common LFI patterns such as ../, %2e%2e%2f, or PHP wrapper streams
• Monitor for unexpected outbound connections from the web server that could indicate successful RFI exploitation
• Implement regular security scans of WordPress installations to identify vulnerable plugin versions

How to Mitigate CVE-2025-22311

Immediate Actions Required

• Update the Private Messages for UserPro plugin to a patched version if available from the vendor
• If no patch is available, deactivate and remove the userpro-messaging plugin until a security update is released
• Review WordPress access logs for any evidence of exploitation attempts
• Audit file permissions on the WordPress installation to ensure restrictive access controls

Patch Information

Security advisory information is available through Patchstack WordPress Vulnerability Database. Site administrators should check with DeluxeThemes for an official security patch addressing this vulnerability. Until a patch is available, consider implementing the workarounds below.

Workarounds

• Disable the Private Messages for UserPro plugin entirely until a security patch is available
• Implement WAF rules to block requests containing directory traversal sequences targeting the plugin
• Restrict PHP's allow_url_include directive to Off in php.ini to prevent remote file inclusion
• Apply file system permissions to limit the web server's ability to read sensitive configuration files

# Configuration example - Disable remote file inclusion in PHP
# Add to php.ini or .user.ini
allow_url_include = Off
allow_url_fopen = Off

# Apache mod_security rule to block LFI attempts
SecRule REQUEST_URI "@contains ../" "id:1001,phase:1,deny,status:403,msg:'Directory traversal attempt blocked'"