CVE-2025-53328: Opinion Stage Plugin Path Traversal Flaw

CVE-2025-53328 Overview

CVE-2025-53328 is a PHP Local File Inclusion (LFI) vulnerability affecting the Opinion Stage Poll, Survey & Quiz Maker WordPress plugin (social-polls-by-opinionstage). This vulnerability stems from improper control of filename parameters in PHP include/require statements, allowing attackers to include local files from the server's filesystem. While classified as a PHP Remote File Inclusion vulnerability type (CWE-98), the actual exploitation vector enables Local File Inclusion attacks against affected WordPress installations.

Critical Impact

Attackers can exploit this vulnerability to read sensitive configuration files, access WordPress credentials, or potentially achieve remote code execution by including files containing malicious code or log files with injected payloads.

Affected Products

• Poll, Survey & Quiz Maker Plugin by Opinion Stage versions through 19.11.0
• WordPress installations running the vulnerable social-polls-by-opinionstage plugin
• Any WordPress site with the Opinion Stage plugin enabled and accessible

Discovery Timeline

• 2025-08-28 - CVE-2025-53328 published to NVD
• 2026-04-15 - Last updated in NVD database

Technical Details for CVE-2025-53328

Vulnerability Analysis

This vulnerability falls under CWE-98 (Improper Control of Filename for Include/Require Statement in PHP Program). The core issue lies in the plugin's failure to properly sanitize user-controlled input before using it in PHP's include() or require() functions. When user input is incorporated into file paths without adequate validation, attackers can manipulate the path to include arbitrary local files from the server.

Local File Inclusion vulnerabilities in WordPress plugins are particularly dangerous because they can expose the wp-config.php file containing database credentials, authentication keys, and other sensitive configuration data. Additionally, if an attacker can control any file on the server (such as through log poisoning or uploaded files), LFI can be escalated to achieve remote code execution.

Root Cause

The vulnerability exists due to insufficient input validation and sanitization in the Opinion Stage plugin's file handling logic. The plugin accepts user-controlled parameters that are subsequently used in PHP include or require statements without proper filtering of directory traversal sequences (such as ../) or validation against an allowlist of permitted files. This design flaw allows attackers to break out of the intended directory structure and access files elsewhere on the filesystem.

Attack Vector

The attack vector for this vulnerability involves manipulating request parameters sent to the WordPress plugin. An attacker can craft malicious requests containing directory traversal sequences to navigate the server's filesystem and include sensitive files. Common exploitation techniques include:

The vulnerability can be exploited by modifying file path parameters to include sequences like ../../../wp-config.php to traverse up the directory structure and access the WordPress configuration file. Attackers may also attempt log poisoning techniques, where malicious PHP code is injected into server log files, which are then included via the LFI vulnerability to achieve code execution.

For detailed technical analysis and exploitation details, refer to the Patchstack Vulnerability Advisory.

Detection Methods for CVE-2025-53328

Indicators of Compromise

• Suspicious HTTP requests containing directory traversal sequences (../, ..%2f, %2e%2e/) targeting the Opinion Stage plugin endpoints
• Access attempts to sensitive files like wp-config.php, /etc/passwd, or server log files through plugin parameters
• Unusual file access patterns in server logs originating from the social-polls-by-opinionstage plugin directory
• Error messages indicating failed file inclusion attempts or path manipulation

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block requests containing path traversal patterns targeting WordPress plugin endpoints
• Configure intrusion detection systems (IDS) to alert on HTTP requests with LFI signatures such as null bytes, encoded traversal sequences, and wrapper protocol attempts
• Review WordPress access logs for requests to Opinion Stage plugin files with suspicious query parameters
• Deploy SentinelOne Singularity to monitor for anomalous file access patterns and PHP process behaviors indicative of LFI exploitation

Monitoring Recommendations

• Enable verbose logging for the WordPress application and monitor for file inclusion errors or warnings
• Set up alerts for access to sensitive configuration files from unexpected PHP processes
• Monitor for unusual outbound data transfers that may indicate successful exfiltration of configuration data
• Implement file integrity monitoring on critical WordPress files to detect unauthorized access or modifications

How to Mitigate CVE-2025-53328

Immediate Actions Required

• Update the Opinion Stage Poll, Survey & Quiz Maker plugin to a version newer than 19.11.0 once a patched version is available
• If updates are not immediately available, consider temporarily disabling the social-polls-by-opinionstage plugin until a fix is released
• Implement WAF rules to block path traversal attempts targeting WordPress plugin endpoints
• Review server logs for evidence of exploitation attempts and investigate any suspicious activity

Patch Information

Organizations should monitor the official Opinion Stage plugin repository and the Patchstack Vulnerability Advisory for updates regarding security patches. Apply any security updates as soon as they become available through the WordPress plugin update mechanism.

Workarounds

• Temporarily deactivate the Opinion Stage plugin if it is not critical to site operations
• Implement server-level restrictions using open_basedir PHP directive to limit file inclusion to specific directories
• Configure ModSecurity or similar WAF with OWASP Core Rule Set to block LFI attack patterns
• Restrict file permissions on sensitive configuration files to minimize exposure in case of successful exploitation

# Configuration example for Apache .htaccess to block common LFI patterns
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{QUERY_STRING} (\.\./|\.\.\\) [NC,OR]
    RewriteCond %{QUERY_STRING} (boot\.ini|etc/passwd|self/environ) [NC,OR]
    RewriteCond %{QUERY_STRING} (wp-config\.php) [NC]
    RewriteRule .* - [F,L]
</IfModule>