CVE-2026-25326: CMSMasters Content Composer LFI Vulnerability

CVE-2026-25326 Overview

CVE-2026-25326 is a Local File Inclusion (LFI) vulnerability affecting the CMSMasters Content Composer WordPress plugin. 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 vulnerability is classified under CWE-98 (Improper Control of Filename for Include/Require Statement in PHP Program), which describes weaknesses where PHP applications fail to properly validate or sanitize filenames before using them in include or require operations.

Critical Impact

Attackers can potentially read sensitive configuration files, access credentials stored on the server, or chain this vulnerability with other techniques to achieve remote code execution on affected WordPress installations.

Affected Products

• CMSMasters Content Composer plugin versions up to and including 1.4.5
• WordPress installations running vulnerable versions of the cmsmasters-content-composer plugin

Discovery Timeline

• 2026-02-19 - CVE-2026-25326 published to NVD
• 2026-02-19 - Last updated in NVD database

Technical Details for CVE-2026-25326

Vulnerability Analysis

The CMSMasters Content Composer plugin contains a PHP Local File Inclusion vulnerability that arises from insufficient input validation on user-controllable parameters. When the plugin processes certain requests, it accepts filename input that is subsequently passed to PHP's include or require functions without adequate sanitization.

Local File Inclusion vulnerabilities in WordPress plugins are particularly dangerous because they can expose sensitive WordPress configuration files such as wp-config.php, which contains database credentials and authentication keys. Furthermore, if an attacker can combine this LFI with the ability to upload files or control log file contents, they may achieve remote code execution.

The vulnerability affects all versions of the plugin from the initial release through version 1.4.5, indicating that this issue has been present in the plugin's codebase without remediation across multiple releases.

Root Cause

The root cause of this vulnerability is the improper control of filename parameters in PHP include/require statements. The plugin fails to implement proper input validation, path normalization, or allowlist-based file restrictions before including files based on user input. This allows attackers to manipulate file path parameters to traverse directories or specify arbitrary local files for inclusion.

Attack Vector

The attack vector involves submitting crafted requests to the vulnerable plugin endpoint with manipulated filename parameters. An attacker can leverage path traversal sequences (such as ../) or absolute paths to reference sensitive files outside the intended directory scope.

Typical attack scenarios include:

1. Configuration File Disclosure: Reading wp-config.php to obtain database credentials
2. Log File Poisoning: If the attacker can inject PHP code into log files, they can then include those logs to execute arbitrary code
3. Sensitive Data Exposure: Accessing /etc/passwd or other system files to enumerate users and system configuration

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

Detection Methods for CVE-2026-25326

Indicators of Compromise

• Unusual HTTP requests to WordPress endpoints containing path traversal sequences (../, ..%2f, ..%5c)
• Web server access logs showing attempts to access sensitive files like wp-config.php, /etc/passwd, or log files
• Requests containing null byte sequences (%00) or encoded path separators targeting the cmsmasters-content-composer plugin
• Unexpected file access patterns in application logs indicating inclusion of files outside normal plugin directories

Detection Strategies

• Deploy Web Application Firewall (WAF) rules to detect and block path traversal patterns in requests to WordPress installations
• Monitor server access logs for requests containing directory traversal sequences targeting the /wp-content/plugins/cmsmasters-content-composer/ path
• Implement file integrity monitoring to detect unauthorized access attempts to sensitive configuration files
• Configure intrusion detection systems (IDS) to alert on LFI attack patterns in HTTP traffic

Monitoring Recommendations

• Enable detailed logging for the WordPress installation and review logs regularly for suspicious activity
• Monitor for unusual PHP error messages that may indicate failed file inclusion attempts
• Set up alerts for access attempts to critical files such as wp-config.php from unexpected sources
• Track plugin activity and API calls that involve file operations or dynamic includes

How to Mitigate CVE-2026-25326

Immediate Actions Required

• Update the CMSMasters Content Composer plugin to a patched version when available from the vendor
• If no patch is available, consider temporarily deactivating the cmsmasters-content-composer plugin until a security update is released
• Implement Web Application Firewall rules to block path traversal attempts at the network perimeter
• Review WordPress file permissions to ensure the web server process has minimal required access
• Audit your WordPress installation for any signs of compromise or unauthorized file access

Patch Information

Plugin users should monitor the CMSMasters vendor channels and WordPress plugin repository for security updates addressing this vulnerability. The Patchstack WordPress Vulnerability Report provides additional details and may be updated with patch availability information.

Workarounds

• Temporarily disable the CMSMasters Content Composer plugin if it is not essential for site functionality
• Implement strict input validation at the server level using ModSecurity or similar WAF solutions
• Restrict PHP open_basedir to limit which directories PHP can access, reducing the impact of successful exploitation
• Configure server-level access controls to prevent the web server from reading sensitive system files
• Consider implementing a virtual patching solution through a security plugin while awaiting an official fix

# Example ModSecurity rule to block path traversal attempts
SecRule REQUEST_URI "@contains cmsmasters-content-composer" \
  "chain,id:100001,phase:1,deny,status:403,log,msg:'Potential LFI attempt blocked'"
SecRule ARGS "@rx (\.\./|\.\.\\\\)" "t:urlDecodeUni"