CVE-2026-28054: Legal Stone PHP File Inclusion Vulnerability

CVE-2026-28054 Overview

CVE-2026-28054 is a Local File Inclusion (LFI) vulnerability affecting the ThemeREX Legal Stone WordPress theme. The vulnerability stems from improper control of filename parameters used in PHP include/require statements, allowing attackers to include arbitrary local files from the server's filesystem. This can lead to sensitive information disclosure, configuration file exposure, and potentially remote code execution when combined with other attack techniques.

Critical Impact

Attackers can exploit this vulnerability to read sensitive files from the web server, potentially exposing database credentials, WordPress configuration files, and other sensitive system information. In advanced scenarios, this could be chained with log poisoning or file upload vulnerabilities to achieve remote code execution.

Affected Products

• ThemeREX Legal Stone WordPress Theme versions up to and including 1.2.11
• WordPress installations using the vulnerable Legal Stone theme
• Web servers hosting affected WordPress sites

Discovery Timeline

• 2026-03-05 - CVE CVE-2026-28054 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28054

Vulnerability Analysis

This vulnerability is classified as CWE-98 (Improper Control of Filename for Include/Require Statement in PHP Program). The Legal Stone WordPress theme fails to properly validate and sanitize user-controlled input before using it in PHP include or require statements. This allows attackers to manipulate file path parameters to traverse directories and include arbitrary local files from the server.

The attack can be executed remotely without authentication, though it requires some level of sophistication to successfully exploit. When successful, attackers gain access to read arbitrary files from the server's filesystem within the web server's permission scope. This can expose sensitive configuration files such as wp-config.php, .htaccess, and system files like /etc/passwd.

Root Cause

The root cause of this vulnerability is insufficient input validation in the ThemeREX Legal Stone theme. The theme accepts user-supplied input for file path parameters and passes it directly to PHP's include or require functions without adequate sanitization. This allows path traversal sequences (such as ../) to be injected, enabling attackers to navigate outside intended directories and include sensitive files.

The lack of a whitelist approach for allowed files and the absence of proper canonicalization before file inclusion creates this security gap. Modern secure coding practices require strict validation of any user input used in filesystem operations.

Attack Vector

The vulnerability can be exploited over the network without authentication. An attacker sends specially crafted HTTP requests containing path traversal sequences to the vulnerable WordPress theme endpoint. The malicious payload manipulates file inclusion parameters to reference files outside the intended directory structure.

A typical attack scenario involves an attacker targeting a known vulnerable endpoint in the Legal Stone theme, injecting path traversal sequences to read sensitive files like wp-config.php which contains database credentials. More sophisticated attacks may chain this LFI with log poisoning techniques, where attackers inject PHP code into server logs and then use the LFI to include and execute those logs, achieving remote code execution.

Detection Methods for CVE-2026-28054

Indicators of Compromise

• HTTP request logs containing path traversal patterns such as ../, ..%2f, or ..%252f targeting Legal Stone theme endpoints
• Unusual access patterns to theme files, particularly requests with excessively long paths or encoded characters
• Error logs showing PHP include/require warnings for unexpected file paths
• Web application firewall alerts for LFI or path traversal attack signatures

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block path traversal patterns in request parameters
• Implement file integrity monitoring on WordPress installations to detect unauthorized file access
• Configure intrusion detection systems to alert on LFI attack signatures targeting WordPress themes
• Review web server access logs for requests containing directory traversal sequences

Monitoring Recommendations

• Enable detailed PHP error logging to capture failed file inclusion attempts
• Monitor WordPress theme directory access patterns for anomalous file read operations
• Set up real-time alerting for WAF rule triggers related to file inclusion attacks
• Implement behavioral analysis to detect unusual file access patterns from web server processes

How to Mitigate CVE-2026-28054

Immediate Actions Required

• Update the Legal Stone theme to the latest patched version when available from ThemeREX
• If no patch is available, consider temporarily disabling or removing the Legal Stone theme
• Implement web application firewall rules to block path traversal attempts
• Review server access logs for signs of exploitation attempts

Patch Information

Organizations should monitor the Patchstack WordPress Vulnerability Report for updates regarding patches and remediation guidance. Contact ThemeREX directly for information about security updates for the Legal Stone theme. Ensure WordPress core and all other plugins and themes are kept up to date to minimize overall attack surface.

Workarounds

• Implement strict WAF rules to filter and block requests containing path traversal sequences (../, ..%2f, encoded variants)
• Use WordPress security plugins that provide virtual patching capabilities for known vulnerabilities
• Apply the principle of least privilege to web server file permissions, restricting access to sensitive files
• Consider using PHP open_basedir configuration to restrict file system access for PHP scripts

# Apache mod_security configuration example to block path traversal
SecRule REQUEST_URI|ARGS|ARGS_NAMES "@contains ../" \
    "id:1001,phase:1,deny,status:403,log,msg:'Path traversal attempt blocked'"
    
# PHP open_basedir restriction in php.ini
# open_basedir = /var/www/html:/tmp