CVE-2026-22399: Holmes Theme PHP File Inclusion Flaw

CVE-2026-22399 Overview

CVE-2026-22399 is a Local File Inclusion (LFI) vulnerability in the Holmes WordPress theme developed by Mikado-Themes. The vulnerability stems from improper control of filename for include/require statements in PHP (CWE-98), allowing attackers to include local files from the server's filesystem through manipulated input parameters.

Critical Impact

Attackers can exploit this LFI vulnerability to read sensitive files from the server, potentially exposing configuration files, credentials, or other sensitive data. In certain configurations, this could be chained with other techniques to achieve remote code execution.

Affected Products

• Holmes WordPress Theme version 1.7 and earlier
• All WordPress installations using vulnerable Holmes theme versions

Discovery Timeline

• 2026-03-05 - CVE CVE-2026-22399 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-22399

Vulnerability Analysis

This vulnerability is classified under CWE-98 (Improper Control of Filename for Include/Require Statement in PHP Program). The Holmes WordPress theme fails to properly validate and sanitize user-supplied input before using it in PHP file inclusion operations. This allows an attacker to manipulate file paths and include arbitrary local files from the web server.

Local File Inclusion vulnerabilities in WordPress themes are particularly dangerous because they can be exploited by unauthenticated attackers in many cases, and WordPress installations often contain sensitive configuration files including wp-config.php which stores database credentials.

Root Cause

The root cause of this vulnerability lies in the improper handling of user-controllable input that is passed to PHP's include(), require(), include_once(), or require_once() functions. The Holmes theme does not implement sufficient input validation or path sanitization, allowing directory traversal sequences (such as ../) to be processed, enabling attackers to escape the intended directory and access files elsewhere on the filesystem.

Attack Vector

An attacker can exploit this vulnerability by crafting malicious requests that manipulate file path parameters accepted by the vulnerable theme component. The attack typically involves using directory traversal sequences to navigate the filesystem and include sensitive files such as /etc/passwd on Linux systems or WordPress configuration files like wp-config.php.

The vulnerability can be exploited remotely through HTTP requests to the affected WordPress installation. Successful exploitation allows reading of arbitrary files accessible to the web server process, which may include:

• WordPress configuration files containing database credentials
• System files revealing server configuration
• Log files containing sensitive information
• Other application source code files

For detailed technical information about this vulnerability, refer to the Patchstack WordPress Vulnerability Notice.

Detection Methods for CVE-2026-22399

Indicators of Compromise

• Unusual HTTP requests containing directory traversal patterns (../, ..%2f, %2e%2e/) targeting Holmes theme endpoints
• Web server access logs showing requests attempting to access sensitive files like /etc/passwd or wp-config.php
• Error logs indicating failed file inclusion attempts or unexpected file access patterns
• Anomalous requests to Holmes theme assets with suspicious query parameters

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block directory traversal patterns in requests
• Monitor web server access logs for patterns indicative of LFI exploitation attempts
• Implement file integrity monitoring on critical WordPress files and system configuration files
• Use security plugins that can detect and alert on suspicious request patterns

Monitoring Recommendations

• Configure alerting for any access attempts to sensitive system files through web requests
• Establish baseline traffic patterns for the Holmes theme and alert on anomalies
• Review web server logs regularly for indicators of exploitation attempts
• Enable verbose logging for PHP errors to capture failed inclusion attempts

How to Mitigate CVE-2026-22399

Immediate Actions Required

• Disable or remove the Holmes theme from WordPress installations until a patched version is available
• Switch to an alternative, secure WordPress theme
• Implement WAF rules to block directory traversal patterns
• Review server logs for any indicators of prior exploitation

Patch Information

At the time of publication, users should check the Patchstack advisory for the latest patch status and updates from Mikado-Themes. Upgrade to a patched version when available, or consider replacing the theme with a secure alternative.

Workarounds

• Implement server-side input validation to reject requests containing directory traversal sequences
• Configure open_basedir PHP directive to restrict file access to the WordPress directory
• Use a Web Application Firewall to filter malicious requests before they reach the application
• Apply the principle of least privilege to the web server process to limit accessible files

# PHP configuration to restrict file access (php.ini or .htaccess)
# Add to php.ini to restrict PHP file access to WordPress directory
open_basedir = /var/www/html/wordpress/

# Apache .htaccess rule to block directory traversal
RewriteEngine On
RewriteCond %{QUERY_STRING} (\.|%2e)(\.|%2e)(\/|%2f) [NC]
RewriteRule .* - [F,L]