CVE-2026-28091: ThemeREX Coleo LFI Vulnerability

CVE-2026-28091 Overview

CVE-2026-28091 is a Local File Inclusion (LFI) vulnerability affecting the ThemeREX Coleo 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 filesystem. This vulnerability is classified under CWE-98 (Improper Control of Filename for Include/Require Statement in PHP Program).

Critical Impact

Successful exploitation allows attackers to read sensitive files, potentially exposing configuration data, credentials, or source code. In certain configurations, this could be chained with other techniques to achieve remote code execution.

Affected Products

• ThemeREX Coleo WordPress Theme version 1.1.7 and earlier
• WordPress installations using vulnerable Coleo theme versions

Discovery Timeline

• 2026-03-05 - CVE-2026-28091 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-28091

Vulnerability Analysis

This Local File Inclusion vulnerability exists within the ThemeREX Coleo WordPress theme due to insufficient validation and sanitization of user-controlled input that is subsequently used in PHP include() or require() functions. The vulnerability allows attackers to manipulate file path parameters to include arbitrary files from the local filesystem.

LFI vulnerabilities in WordPress themes are particularly dangerous because they can be exploited to read sensitive WordPress configuration files such as wp-config.php, which contains database credentials and authentication keys. Additionally, attackers may leverage this vulnerability to include log files containing injected PHP code, potentially escalating to remote code execution.

Root Cause

The root cause is improper control of filename parameters in PHP include/require statements. The Coleo theme fails to properly validate and sanitize user-supplied input before using it in file inclusion operations. This allows path traversal sequences (such as ../) to be processed, enabling attackers to escape the intended directory and access files elsewhere on the server.

Attack Vector

The vulnerability is exploitable over the network without authentication. An attacker can craft malicious HTTP requests containing path traversal sequences targeting vulnerable PHP files within the Coleo theme. The attack complexity is considered high due to specific conditions that must be met for successful exploitation.

The exploitation typically involves:

1. Identifying vulnerable inclusion points within the Coleo theme
2. Crafting requests with path traversal sequences (e.g., ../../../) to navigate to target files
3. Including sensitive files such as /etc/passwd, wp-config.php, or log files
4. Potentially chaining with log poisoning or other techniques for code execution

For detailed technical information, refer to the Patchstack Vulnerability Report.

Detection Methods for CVE-2026-28091

Indicators of Compromise

• Unusual HTTP requests containing path traversal patterns (../, ..%2f, %2e%2e/) targeting the Coleo theme directory
• Web server logs showing access to theme files with suspicious query parameters
• Attempts to access sensitive system files through web requests
• Error logs indicating file access attempts outside normal theme directories

Detection Strategies

• Deploy web application firewall (WAF) rules to detect and block path traversal attempts
• Monitor web server access logs for requests containing encoded or decoded traversal sequences
• Implement file integrity monitoring on critical WordPress files
• Use intrusion detection systems (IDS) with signatures for LFI attack patterns

Monitoring Recommendations

• Enable detailed logging for all requests to the WordPress wp-content/themes/coleo/ directory
• Set up alerts for HTTP requests containing multiple consecutive ../ patterns
• Monitor for unusual file read operations by the web server process
• Review access patterns to sensitive files like wp-config.php from web contexts

How to Mitigate CVE-2026-28091

Immediate Actions Required

• Update the Coleo theme to a version newer than 1.1.7 if a patched version is available from ThemeREX
• If no patch is available, consider temporarily disabling or replacing the Coleo theme
• Implement WAF rules to block path traversal attempts targeting the theme
• Review web server logs for evidence of exploitation attempts

Patch Information

Organizations should monitor ThemeREX for an official security update addressing this vulnerability. The Patchstack advisory provides additional details on the vulnerability and remediation guidance.

Workarounds

• Implement strict WAF rules blocking path traversal sequences in requests to the theme
• Restrict filesystem permissions to limit what files the web server can read
• Use open_basedir PHP configuration to restrict file access to the WordPress directory
• Consider switching to an alternative WordPress theme until a patch is available

# PHP configuration mitigation - add to php.ini or .htaccess
# Restrict PHP file operations to WordPress directory
php_value open_basedir /var/www/html/wordpress/

# Apache mod_rewrite rules to block traversal attempts
RewriteEngine On
RewriteCond %{QUERY_STRING} (\.\./|\.\.%2f|%2e%2e/) [NC]
RewriteRule ^wp-content/themes/coleo/ - [F,L]