CVE-2026-28094: RexCoin PHP File Inclusion Vulnerability

CVE-2026-28094 Overview

CVE-2026-28094 is a Local File Inclusion (LFI) vulnerability affecting the ThemeREX RexCoin WordPress theme. The vulnerability stems from improper control of filename for include/require statements in PHP, classified under CWE-98 (PHP Remote File Inclusion). An attacker can exploit this flaw to include arbitrary local files on the server, potentially leading to sensitive information disclosure, configuration exposure, or code execution through log poisoning or other advanced techniques.

Critical Impact

This vulnerability allows unauthenticated attackers to include local files on the server, potentially exposing sensitive configuration files such as wp-config.php, system credentials, or enabling further exploitation through log file poisoning techniques.

Affected Products

• ThemeREX RexCoin WordPress Theme versions up to and including 1.2.6
• WordPress installations using the vulnerable RexCoin theme
• All server configurations running affected RexCoin theme versions

Discovery Timeline

• 2026-03-05 - CVE CVE-2026-28094 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28094

Vulnerability Analysis

This vulnerability is categorized as CWE-98: Improper Control of Filename for Include/Require Statement in PHP Program. The RexCoin WordPress theme fails to properly validate and sanitize user-supplied input before using it in PHP include(), require(), or similar file inclusion functions.

Local File Inclusion vulnerabilities occur when an application dynamically includes files based on user-controllable input without adequate path sanitization. In the context of WordPress themes, this typically manifests through template loading mechanisms, AJAX handlers, or custom functionality that processes file paths from request parameters.

The vulnerability can be exploited over the network without authentication, though exploitation requires high complexity due to the nature of LFI attacks. Successful exploitation could result in confidentiality, integrity, and availability impacts as attackers gain access to sensitive server files or achieve code execution.

Root Cause

The root cause of this vulnerability lies in insufficient input validation within the RexCoin theme's PHP code. The theme likely accepts user-supplied parameters that influence file inclusion operations without proper sanitization, allowing attackers to manipulate file paths using directory traversal sequences (e.g., ../) to access files outside the intended directory scope.

Common vulnerable patterns include:

• Direct use of $_GET or $_POST parameters in include() or require() statements
• Inadequate filtering of directory traversal characters
• Missing allowlist validation for permitted file paths
• Failure to use WordPress core functions designed for safe file handling

Attack Vector

The attack vector is network-based, meaning exploitation can occur remotely through HTTP requests to the vulnerable WordPress installation. An attacker would craft malicious requests containing manipulated file path parameters to trigger the inclusion of arbitrary local files.

Typical exploitation scenarios include:

• Reading sensitive configuration files like wp-config.php containing database credentials
• Accessing /etc/passwd or other system files for reconnaissance
• Including log files containing injected PHP code (log poisoning) to achieve remote code execution
• Extracting theme or plugin source code for further vulnerability analysis

Due to the high complexity requirement, successful exploitation may depend on specific server configurations, file permissions, and the attacker's ability to craft appropriate traversal sequences.

Detection Methods for CVE-2026-28094

Indicators of Compromise

• Unusual HTTP requests containing directory traversal patterns such as ../ or ..%2f in parameters directed at the RexCoin theme
• Access logs showing requests to theme endpoints with file path manipulation attempts
• Server logs indicating PHP errors related to file inclusion from unexpected directories
• Evidence of sensitive file access in server logs, such as requests attempting to include /etc/passwd or wp-config.php

Detection Strategies

• Configure Web Application Firewall (WAF) rules to detect and block requests containing directory traversal sequences targeting WordPress theme endpoints
• Implement file integrity monitoring to detect unauthorized access to sensitive configuration files
• Enable verbose PHP error logging and monitor for file inclusion warnings or errors from unexpected paths
• Deploy endpoint detection solutions capable of identifying suspicious PHP process behavior

Monitoring Recommendations

• Review web server access logs for requests to RexCoin theme files containing unusual path parameters
• Set up alerts for HTTP requests matching LFI attack patterns in security monitoring systems
• Monitor for unexpected file read operations by the web server process, particularly targeting sensitive system or configuration files
• Implement log analysis to identify repeated failed file inclusion attempts that may indicate exploitation attempts

How to Mitigate CVE-2026-28094

Immediate Actions Required

• Deactivate and remove the RexCoin theme immediately if running version 1.2.6 or earlier
• Contact ThemeREX for information regarding a patched version of the RexCoin theme
• Review web server access logs for evidence of exploitation attempts
• Audit WordPress file permissions to restrict access to sensitive configuration files
• Implement WAF rules to block directory traversal patterns targeting theme endpoints

Patch Information

As of the current data, specific patch details are not available. Organizations should monitor the Patchstack Vulnerability Report for updates on remediation guidance and patched versions from ThemeREX. Users are advised to check for theme updates in their WordPress dashboard and apply any security patches as soon as they become available.

Workarounds

• Switch to an alternative WordPress theme until a patched version of RexCoin is released
• Implement strict WAF rules to filter directory traversal sequences in HTTP requests
• Apply PHP open_basedir restrictions to limit file access scope for the web server process
• Disable direct access to theme PHP files where possible using .htaccess or server configuration rules

# Example .htaccess rule to block directory traversal attempts
# Place in WordPress root or theme directory
RewriteEngine On
RewriteCond %{QUERY_STRING} (\.\./|\.\.) [NC,OR]
RewriteCond %{QUERY_STRING} (\.\.%2f|\.\.%5c) [NC]
RewriteRule .* - [F,L]