CVE-2026-22371: Gustavo Theme File Inclusion Vulnerability

CVE-2026-22371 Overview

CVE-2026-22371 is a PHP Local File Inclusion (LFI) vulnerability affecting the AncoraThemes Gustavo WordPress theme. The vulnerability arises 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 if combined with other attack vectors.

Critical Impact

Unauthenticated attackers can exploit this LFI vulnerability to read sensitive server files, potentially exposing database credentials, API keys, and WordPress configuration data, which may lead to full site compromise.

Affected Products

• AncoraThemes Gustavo WordPress Theme version 1.2.2 and earlier
• WordPress installations using the Gustavo theme
• All WordPress sites running vulnerable Gustavo theme versions

Discovery Timeline

• 2026-02-20 - CVE CVE-2026-22371 published to NVD
• 2026-02-24 - Last updated in NVD database

Technical Details for CVE-2026-22371

Vulnerability Analysis

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

The network-based attack vector requires no authentication or user interaction, though the complexity is considered high due to the conditions that must be met for successful exploitation. When exploited, attackers can read sensitive files such as wp-config.php, which contains database credentials, authentication keys, and other critical WordPress configuration data.

Root Cause

The root cause of this vulnerability lies in insufficient input validation within the Gustavo theme's PHP code. The theme accepts user-controlled input that is directly or indirectly passed to PHP's include(), require(), include_once(), or require_once() functions without proper sanitization. This allows attackers to inject directory traversal sequences (such as ../) to navigate outside the intended directory structure and include sensitive files.

Attack Vector

The attack is executed remotely over the network without requiring authentication. An attacker crafts malicious requests containing path traversal sequences to target PHP endpoints within the Gustavo theme that improperly handle file inclusion parameters. By manipulating these parameters, the attacker can include files such as /etc/passwd, wp-config.php, or other sensitive configuration files. If log files containing attacker-controlled content can be included, this LFI vulnerability may be escalated to remote code execution through log poisoning techniques.

The vulnerability requires specific conditions to be exploitable, including the presence of targeted files and proper path construction, contributing to the high attack complexity rating.

Detection Methods for CVE-2026-22371

Indicators of Compromise

• Unusual HTTP requests containing directory traversal patterns (../, ..%2f, %2e%2e/) targeting Gustavo theme endpoints
• Access log entries showing attempts to include system files like /etc/passwd or WordPress configuration files
• Requests with encoded path traversal sequences targeting theme PHP files
• Suspicious file access patterns in PHP error logs indicating failed or successful file inclusions

Detection Strategies

• Monitor web server access logs for path traversal patterns in requests to /wp-content/themes/gustavo/ endpoints
• Implement Web Application Firewall (WAF) rules to block requests containing directory traversal sequences
• Enable PHP error logging and monitor for file inclusion warnings or errors
• Use file integrity monitoring to detect unauthorized access to sensitive configuration files

Monitoring Recommendations

• Configure real-time alerting for suspicious requests containing ../ or encoded variants targeting WordPress theme directories
• Implement log aggregation and SIEM correlation rules for LFI attack patterns
• Monitor for unusual read operations on wp-config.php and other sensitive WordPress files
• Enable WordPress audit logging to track theme-related file access attempts

How to Mitigate CVE-2026-22371

Immediate Actions Required

• Update the Gustavo theme to a patched version immediately if available from AncoraThemes
• Temporarily disable or remove the Gustavo theme if no patch is available
• Implement WAF rules to block path traversal attempts targeting the theme
• Review server access logs for evidence of exploitation attempts

Patch Information

Users should check the Patchstack WordPress Theme Vulnerability advisory for updates on available patches. Contact AncoraThemes directly for information on updated theme versions that address this vulnerability. All Gustavo theme versions through 1.2.2 are confirmed vulnerable.

Workarounds

• Switch to an alternative WordPress theme until a patched version of Gustavo is available
• Implement server-level restrictions using .htaccess or nginx configuration to block malicious requests
• Use a WAF such as Wordfence, Sucuri, or Cloudflare with LFI protection rules enabled
• Restrict PHP's open_basedir directive to limit file inclusion to the WordPress directory structure
• Apply the principle of least privilege to filesystem permissions, ensuring the web server user cannot read sensitive system files

# Apache .htaccess configuration to block path traversal attempts
<IfModule mod_rewrite.c>
    RewriteEngine On
    # Block requests containing path traversal sequences
    RewriteCond %{QUERY_STRING} (\.\./|\.\.%2f|%2e%2e/) [NC,OR]
    RewriteCond %{REQUEST_URI} (\.\./|\.\.%2f|%2e%2e/) [NC]
    RewriteRule .* - [F,L]
</IfModule>

# PHP open_basedir restriction in php.ini or .user.ini
# Limit PHP file access to WordPress directory only
open_basedir = /var/www/html/wordpress/:/tmp/