CVE-2026-24538: Omnipress PHP File Inclusion Vulnerability

CVE-2026-24538 Overview

CVE-2026-24538 is a Local File Inclusion (LFI) vulnerability affecting the Omnipress WordPress plugin developed by omnipressteam. The vulnerability stems from improper control of filename for include/require statements in PHP, classified under CWE-98 (PHP Remote File Inclusion). Despite the CWE classification suggesting remote file inclusion, this specific vulnerability allows PHP Local File Inclusion attacks, enabling authenticated attackers to include arbitrary local files on the server through manipulated input parameters.

Critical Impact

Authenticated attackers can exploit this vulnerability to read sensitive server files, potentially leading to information disclosure, credential theft, or further exploitation through PHP filter chains to achieve remote code execution.

Affected Products

• Omnipress WordPress Plugin versions through 1.6.6
• WordPress installations with vulnerable Omnipress plugin installed
• Web servers hosting affected WordPress sites

Discovery Timeline

• 2026-01-23 - CVE-2026-24538 published to NVD
• 2026-01-26 - Last updated in NVD database

Technical Details for CVE-2026-24538

Vulnerability Analysis

This vulnerability exists within the Omnipress WordPress plugin, which fails to properly sanitize and validate user-controlled input before using it in PHP include or require statements. The attack requires network access and low-privilege authentication (such as a subscriber or contributor role), but requires no user interaction to exploit. When successfully exploited, the vulnerability allows attackers to include local files from the server's filesystem within the PHP execution context.

The impact includes high confidentiality breach as attackers can read sensitive files including configuration files (such as wp-config.php), server logs, and other protected resources. Additionally, there is potential for low-level integrity and availability impacts through advanced exploitation techniques like PHP filter chain attacks.

Root Cause

The root cause is inadequate input validation in the Omnipress plugin's file handling mechanisms. The plugin accepts user-supplied input that directly influences which files are included via PHP's include() or require() functions without proper sanitization. This allows attackers to traverse the directory structure and include files outside the intended scope using path traversal sequences or PHP wrappers.

Attack Vector

The attack is conducted over the network against WordPress sites running the vulnerable Omnipress plugin. An authenticated user with low privileges can craft malicious requests containing manipulated file paths. The vulnerability allows the use of techniques such as:

• Directory traversal sequences (../) to access files outside the web root
• PHP stream wrappers (like php://filter) to encode and extract file contents
• Inclusion of sensitive WordPress configuration files containing database credentials
• Potential chaining with other vulnerabilities for privilege escalation

Attackers typically target files like /etc/passwd, wp-config.php, or application logs to gather sensitive information for further attacks. For detailed technical analysis, refer to the Patchstack vulnerability database entry.

Detection Methods for CVE-2026-24538

Indicators of Compromise

• Unusual HTTP requests containing path traversal sequences (../, ..%2f) targeting Omnipress plugin endpoints
• Requests containing PHP wrappers such as php://filter, php://input, or data://
• Access attempts to sensitive files like wp-config.php or /etc/passwd through plugin parameters
• Anomalous read access to configuration files from web server processes

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block path traversal patterns in requests
• Monitor WordPress access logs for requests containing suspicious file inclusion patterns targeting the Omnipress plugin
• Deploy endpoint detection and response (EDR) solutions to identify file access anomalies
• Use file integrity monitoring to detect unauthorized reads of sensitive configuration files

Monitoring Recommendations

• Enable verbose logging for WordPress and the web server to capture detailed request information
• Set up alerts for requests containing ..%2f, php://filter, or similar LFI indicators
• Monitor for unusual outbound data transfers that could indicate exfiltration of stolen credentials
• Review authentication logs for suspicious login attempts following potential credential exposure

How to Mitigate CVE-2026-24538

Immediate Actions Required

• Update the Omnipress plugin to a patched version if available from the WordPress plugin repository
• If no patch is available, immediately deactivate and remove the Omnipress plugin from affected WordPress installations
• Audit WordPress user accounts and remove unnecessary low-privilege accounts that could be used to exploit this vulnerability
• Review server access logs for evidence of exploitation attempts

Patch Information

Organizations should monitor the WordPress plugin repository and Patchstack vulnerability database for official patch releases from omnipressteam. Until a patch is available, the recommended action is to deactivate the plugin.

Workarounds

• Implement strict Web Application Firewall rules to block requests containing path traversal sequences and PHP wrapper schemes
• Restrict WordPress user registrations and limit the number of authenticated users with plugin access
• Apply the principle of least privilege by restricting PHP's open_basedir directive to limit file access scope
• Consider using security plugins that provide virtual patching capabilities for vulnerable WordPress plugins

# Apache .htaccess rule to block common LFI patterns
<IfModule mod_rewrite.c>
    RewriteEngine On
    RewriteCond %{QUERY_STRING} (\.\.\/|\.\.%2f|php://|data://) [NC]
    RewriteRule ^(.*)$ - [F,L]
</IfModule>

# PHP open_basedir restriction in php.ini or virtual host
# Limits PHP file access to specific directories
# open_basedir = /var/www/html:/tmp