CVE-2026-30694: DedeCMS RCE Vulnerability

CVE-2026-30694 Overview

A remote code execution vulnerability exists in DedeCMS v.5.7.118 and earlier versions. The vulnerability allows a remote attacker to execute arbitrary code via the array_filter component. DedeCMS is a popular PHP-based content management system, and this vulnerability exposes systems running affected versions to complete compromise by unauthenticated attackers.

Critical Impact

Remote attackers can execute arbitrary code on vulnerable DedeCMS installations, potentially leading to full server compromise, data theft, website defacement, or use of the server for further attacks.

Affected Products

• DedeCMS v.5.7.118
• DedeCMS versions prior to v.5.7.118
• Web servers hosting vulnerable DedeCMS installations

Discovery Timeline

• 2026-03-19 - CVE CVE-2026-30694 published to NVD
• 2026-03-19 - Last updated in NVD database

Technical Details for CVE-2026-30694

Vulnerability Analysis

This vulnerability is a Remote Code Execution (RCE) flaw that stems from improper handling of user-supplied input in the array_filter component of DedeCMS. The array_filter() function in PHP can be exploited when user-controlled data is passed as a callback parameter, allowing attackers to execute arbitrary PHP functions.

The vulnerability exists in the file management functionality of DedeCMS, where insufficient input validation allows attackers to bypass security restrictions and achieve code execution. When exploited, an attacker can upload malicious files or inject code that will be executed by the web server with the privileges of the web application.

Root Cause

The root cause of this vulnerability lies in the unsafe use of PHP's array_filter() function with user-controllable callback parameters. DedeCMS fails to properly validate and sanitize input before passing it to array_filter(), which accepts a callback function name as its second argument. An attacker can manipulate this parameter to call arbitrary PHP functions, including dangerous system-level functions that enable code execution.

Additionally, the file management component contains weaknesses that allow attackers to bypass blacklist-based file extension filtering, enabling the upload of malicious PHP files that can serve as webshells.

Attack Vector

The attack vector for this vulnerability is network-based, allowing remote exploitation without authentication. An attacker can craft malicious HTTP requests targeting the vulnerable array_filter component in DedeCMS. The attack does not require user interaction and can be executed against any publicly accessible DedeCMS installation running a vulnerable version.

The exploitation typically involves:

1. Identifying a vulnerable DedeCMS installation
2. Crafting a malicious request that abuses the array_filter callback mechanism
3. Bypassing file upload restrictions to deploy a webshell
4. Executing arbitrary commands on the underlying server

For detailed technical information about the exploitation mechanism, refer to the CVE-2026-30694 Technical Guide and DedeCMS File Management Exploit Analysis.

Detection Methods for CVE-2026-30694

Indicators of Compromise

• Unusual PHP files appearing in web directories, particularly with obfuscated names or recently modified timestamps
• Web server logs showing requests to file management endpoints with suspicious array_filter parameters
• Unexpected outbound network connections from the web server
• New or modified .php files in upload directories or temporary folders
• Evidence of webshell activity such as encoded command execution patterns in access logs

Detection Strategies

• Monitor web server access logs for requests containing array_filter or callback manipulation attempts
• Implement file integrity monitoring on DedeCMS installation directories to detect unauthorized file modifications
• Deploy web application firewall (WAF) rules to detect and block code injection attempts in PHP callback parameters
• Scan for known webshell signatures in web-accessible directories

Monitoring Recommendations

• Enable detailed logging on the web server to capture full request parameters
• Configure alerts for new PHP file creation in DedeCMS directories
• Monitor for anomalous process spawning from web server processes (e.g., php spawning sh, bash, or cmd)
• Review authentication logs for admin panel access attempts from unusual IP addresses

How to Mitigate CVE-2026-30694

Immediate Actions Required

• Upgrade DedeCMS to a version newer than 5.7.118 if a patch is available from the vendor
• Restrict access to DedeCMS administrative interfaces to trusted IP addresses only
• Implement a web application firewall (WAF) to filter malicious requests targeting the array_filter component
• Review and remove any suspicious files that may have been uploaded to the server
• Consider temporarily disabling the file management functionality if not required

Patch Information

As of the publication date, consult the official DedeCMS project for the latest security updates and patching instructions. Organizations should monitor the CVE-2026-30694 Technical Guide for updated remediation guidance.

Workarounds

• Apply strict input validation on all user-supplied parameters, especially those passed to callback functions
• Implement allowlist-based file upload restrictions instead of blacklist filtering
• Use PHP's disable_functions directive in php.ini to disable dangerous functions like exec, system, passthru, and shell_exec
• Restrict write permissions on web directories to prevent unauthorized file creation

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

# Restrict file permissions on DedeCMS directories
chmod -R 755 /var/www/dedecms
chown -R www-data:www-data /var/www/dedecms
chmod -R 555 /var/www/dedecms/uploads