CVE-2026-30457: FuelCMS v1.5.2 RCE Vulnerability

CVE-2026-30457 Overview

A critical remote code execution vulnerability exists in the /parser/dwoo component of Daylight Studio FuelCMS v1.5.2. This vulnerability allows attackers to execute arbitrary code on the target server by injecting crafted PHP code through the Dwoo template parser. The Dwoo parser, which handles template processing within FuelCMS, fails to properly sanitize user-supplied input, enabling malicious actors to bypass security controls and achieve full code execution.

Critical Impact

Successful exploitation allows attackers to execute arbitrary PHP code on the server, potentially leading to complete system compromise, data theft, malware deployment, or lateral movement within the network.

Affected Products

• Daylight Studio FuelCMS v1.5.2
• FuelCMS installations using the Dwoo parser component

Discovery Timeline

• 2026-03-26 - CVE-2026-30457 published to NVD
• 2026-03-26 - Last updated in NVD database

Technical Details for CVE-2026-30457

Vulnerability Analysis

This vulnerability resides in the Dwoo template parsing engine integrated within FuelCMS. The Dwoo parser is responsible for processing template files and rendering dynamic content. However, the implementation in FuelCMS v1.5.2 contains insufficient input validation when processing template directives, allowing attackers to inject and execute arbitrary PHP code.

The vulnerability is classified as a Code Injection flaw that escalates to Remote Code Execution (RCE). When a user-controlled input reaches the Dwoo parser without proper sanitization, the parser interprets and executes the injected PHP code with the same privileges as the web server process.

For additional technical details, refer to the Pentest Tools Vulnerability Report and the GitHub FUEL-CMS Parser Code.

Root Cause

The root cause of this vulnerability is improper input sanitization within the Dwoo template parser component. The parser fails to adequately filter or escape special characters and PHP code constructs before processing template directives. This allows specially crafted input containing PHP code to bypass the intended template processing boundaries and be executed directly by the PHP interpreter.

The Dwoo parser's escape mechanisms can be circumvented through specific payload structures, enabling attackers to break out of the template context and inject executable PHP statements.

Attack Vector

The attack vector involves submitting crafted PHP code through input fields or parameters that are processed by the Dwoo template parser. An attacker can exploit this vulnerability by:

1. Identifying endpoints or template fields that utilize the vulnerable Dwoo parser component
2. Crafting a malicious payload containing PHP code designed to escape the template context
3. Submitting the payload through HTTP requests to the vulnerable FuelCMS installation
4. Achieving arbitrary code execution when the parser processes the malicious input

The attack can be executed remotely without authentication if the vulnerable parser component is exposed to user input. The exploitation complexity is relatively low as it requires only knowledge of the payload structure needed to escape the template context.

Detection Methods for CVE-2026-30457

Indicators of Compromise

• Unusual HTTP requests containing PHP code snippets or template escape sequences targeting /parser/dwoo endpoints
• Web server logs showing requests with encoded PHP functions such as exec(), system(), passthru(), or eval()
• Unexpected processes spawned by the web server process (e.g., www-data, apache, or nginx user)
• New or modified files appearing in the FuelCMS installation directory with unusual content

Detection Strategies

• Implement Web Application Firewall (WAF) rules to detect and block requests containing PHP code injection patterns
• Monitor web server access logs for suspicious requests targeting the /parser/dwoo component path
• Deploy file integrity monitoring on the FuelCMS installation directory to detect unauthorized modifications
• Configure intrusion detection systems (IDS) to alert on outbound connections from the web server to unknown destinations

Monitoring Recommendations

• Enable verbose logging for the FuelCMS application to capture detailed request information
• Implement real-time alerting for any process execution originating from the web server context
• Monitor for unusual network connections originating from the server hosting FuelCMS
• Review PHP error logs for template parsing errors or unexpected code execution attempts

How to Mitigate CVE-2026-30457

Immediate Actions Required

• Restrict access to FuelCMS administrative interfaces and limit exposure to trusted networks only
• Review and sanitize all user inputs before they reach the Dwoo template parser
• Implement strict Content Security Policy (CSP) headers to reduce the impact of potential code execution
• Consider temporarily disabling the Dwoo parser functionality if it is not essential to operations

Patch Information

At the time of publication, check the FuelCMS Official Website and Daylight Official Website for official security patches or updated releases. Users should upgrade to the latest version of FuelCMS as soon as patches become available.

Monitor the official FuelCMS GitHub repository and security channels for patch announcements addressing this vulnerability.

Workarounds

• Implement input validation and output encoding at the application level before data reaches the Dwoo parser
• Deploy a Web Application Firewall (WAF) configured to block requests containing PHP code injection patterns
• Restrict file system permissions for the web server user to prevent write access to sensitive directories
• Consider using PHP's disable_functions directive to restrict dangerous functions like exec(), system(), passthru(), and eval()

# PHP configuration hardening example
# Add to php.ini to disable dangerous functions
disable_functions = exec,passthru,shell_exec,system,proc_open,popen,curl_exec,curl_multi_exec,parse_ini_file,show_source,eval,assert

# Restrict open_basedir to limit file system access
open_basedir = /var/www/fuelcms:/tmp

# Disable allow_url_include to prevent remote file inclusion
allow_url_include = Off