CVE-2026-27994: ThemeREX Tediss File Inclusion Vulnerability

CVE-2026-27994 Overview

CVE-2026-27994 is a Local File Inclusion (LFI) vulnerability in the ThemeREX Tediss WordPress theme. The vulnerability stems from improper control of filename parameters used in PHP include/require statements, which can allow attackers to include arbitrary local files on the server. This type of vulnerability is classified under CWE-98 (Improper Control of Filename for Include/Require Statement in PHP Program).

Critical Impact

Successful exploitation could allow attackers to read sensitive files from the server, potentially exposing configuration files, credentials, or other sensitive data. In some scenarios, this could be chained with other vulnerabilities to achieve remote code execution.

Affected Products

• ThemeREX Tediss WordPress Theme version 1.2.4 and earlier
• WordPress installations running vulnerable versions of the Tediss theme

Discovery Timeline

• 2026-03-05 - CVE-2026-27994 published to NVD
• 2026-03-05 - Last updated in NVD database

Technical Details for CVE-2026-27994

Vulnerability Analysis

The vulnerability exists within the ThemeREX Tediss WordPress theme due to insufficient validation and sanitization of user-controlled input that is passed to PHP's include() or require() functions. When the application constructs file paths using unsanitized user input, attackers can manipulate the filename parameter to include arbitrary files from the local file system.

Local File Inclusion vulnerabilities in PHP applications are particularly dangerous because they can expose sensitive system files such as /etc/passwd, WordPress configuration files containing database credentials (wp-config.php), or log files that may contain sensitive information. In certain configurations, LFI can be escalated to remote code execution through techniques like log poisoning or PHP wrapper exploitation.

Root Cause

The root cause of this vulnerability is the improper handling of user-supplied input in file inclusion operations. The Tediss theme fails to adequately validate or sanitize filename parameters before using them in PHP include/require statements. This allows path traversal sequences (such as ../) to be injected, enabling attackers to navigate outside the intended directory structure and access arbitrary files on the system.

Attack Vector

An attacker can exploit this vulnerability by crafting malicious HTTP requests containing path traversal sequences in parameters that are used by the theme's file inclusion logic. The attack does not require authentication in typical scenarios, making it accessible to remote unauthenticated attackers.

The exploitation typically involves:

1. Identifying parameters that accept file paths or template names
2. Injecting path traversal sequences to navigate to sensitive files
3. Reading the contents of system or application configuration files

Common targets include reading wp-config.php to obtain database credentials, accessing /etc/passwd for user enumeration, or reading log files that may contain session tokens or other sensitive data. For detailed technical information, refer to the Patchstack vulnerability database entry.

Detection Methods for CVE-2026-27994

Indicators of Compromise

• Unusual HTTP requests containing path traversal sequences such as ../, ..%2f, or encoded variants targeting theme endpoints
• Access attempts to sensitive files like wp-config.php, /etc/passwd, or system log files through theme parameters
• Error logs showing file inclusion failures or unexpected file access patterns
• Web server logs with requests containing null bytes or PHP wrapper protocols (php://, data://)

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block path traversal sequences in request parameters
• Monitor web server access logs for requests containing ../ patterns or encoded variants targeting the Tediss theme directories
• Deploy file integrity monitoring to detect unauthorized access attempts to sensitive configuration files
• Configure SentinelOne Singularity Platform to monitor for suspicious PHP file inclusion behavior and path traversal attempts

Monitoring Recommendations

• Enable detailed logging for the WordPress application and web server to capture all request parameters
• Set up alerts for failed file access attempts that indicate traversal attacks
• Monitor for unusual file read operations from the web server process, particularly attempts to access files outside the WordPress installation directory
• Implement network-level monitoring to detect data exfiltration patterns that may follow successful LFI exploitation

How to Mitigate CVE-2026-27994

Immediate Actions Required

• Identify all WordPress installations using the ThemeREX Tediss theme version 1.2.4 or earlier
• Consider temporarily disabling or removing the vulnerable theme until a patch is available
• Implement WAF rules to block path traversal attempts targeting WordPress themes
• Review server logs for any evidence of exploitation attempts
• Restrict file system permissions to limit the impact of potential file inclusion attacks

Patch Information

Users should check the Patchstack vulnerability database and the ThemeREX vendor website for updated versions of the Tediss theme. It is strongly recommended to update to a patched version as soon as one becomes available.

Workarounds

• Deploy a Web Application Firewall with rules configured to block path traversal sequences and PHP wrapper protocols
• Implement PHP's open_basedir directive to restrict file access to the WordPress installation directory
• Use disable_functions in php.ini to disable dangerous functions if not needed
• Apply the principle of least privilege to web server file system permissions, ensuring the web process cannot read sensitive system files
• Consider using WordPress security plugins that provide file inclusion protection

# PHP configuration hardening example
# Add to php.ini or .htaccess

# Restrict PHP file access to WordPress directory
# php_value open_basedir /var/www/html/wordpress:/tmp

# Block common path traversal patterns via .htaccess
# RewriteEngine On
# RewriteCond %{QUERY_STRING} (\.\./|\.\.) [NC]
# RewriteRule .* - [F,L]