CVE-2025-25789: Foxcms Foxcms RCE Vulnerability

CVE-2025-25789 Overview

CVE-2025-25789 is a critical remote code execution (RCE) vulnerability discovered in FoxCMS v1.2.5. The vulnerability exists in the index() method located within the \controller\Sitemap.php file. This code injection flaw allows unauthenticated attackers to execute arbitrary code remotely on affected systems, potentially leading to complete server compromise.

Critical Impact

This vulnerability enables unauthenticated remote code execution, allowing attackers to gain complete control over affected FoxCMS installations without requiring any user interaction or prior authentication.

Affected Products

• FoxCMS v1.2.5
• FoxCMS installations using the vulnerable Sitemap.php controller

Discovery Timeline

• 2025-02-26 - CVE-2025-25789 published to NVD
• 2025-04-09 - Last updated in NVD database

Technical Details for CVE-2025-25789

Vulnerability Analysis

This vulnerability is classified as CWE-94 (Improper Control of Generation of Code), commonly known as Code Injection. The flaw resides in the index() method within the Sitemap.php controller component of FoxCMS. The vulnerability allows attackers to inject and execute arbitrary code on the server due to insufficient input validation and sanitization in the affected method.

The network-accessible nature of this vulnerability means that any FoxCMS instance exposed to the internet is potentially vulnerable. The attack requires no authentication credentials and no user interaction, making it particularly dangerous for publicly accessible installations.

Root Cause

The root cause of this vulnerability is improper input validation in the index() method of the Sitemap.php controller. The code fails to properly sanitize user-controlled input before processing it, allowing malicious code to be injected and executed within the application context. This represents a fundamental failure in following secure coding practices for handling untrusted input.

Attack Vector

The attack vector is network-based, allowing remote exploitation. An attacker can craft malicious HTTP requests targeting the vulnerable Sitemap.php controller endpoint. Since no authentication is required and the attack complexity is low, exploitation can be automated at scale against vulnerable FoxCMS installations.

The exploitation process involves sending specially crafted requests to the index() method that include malicious code payloads. When processed by the vulnerable controller, this code is executed with the privileges of the web server process.

For detailed technical exploitation information, refer to the GitHub RCE Exploit Guide.

Detection Methods for CVE-2025-25789

Indicators of Compromise

• Anomalous HTTP requests targeting /Sitemap.php or related sitemap controller endpoints
• Unusual process spawning from web server processes (PHP, Apache, nginx)
• Unexpected outbound network connections from the web server
• New or modified files in web-accessible directories with suspicious content
• Evidence of webshell deployment or backdoor installations

Detection Strategies

• Implement web application firewall (WAF) rules to detect and block code injection patterns in requests to sitemap endpoints
• Monitor web server access logs for suspicious requests targeting Sitemap.php with unusual parameters
• Deploy endpoint detection and response (EDR) solutions to identify post-exploitation behaviors
• Configure intrusion detection systems (IDS) to alert on patterns consistent with RCE exploitation attempts

Monitoring Recommendations

• Enable detailed logging for all requests to the FoxCMS application, particularly controller endpoints
• Implement file integrity monitoring on FoxCMS installation directories to detect unauthorized modifications
• Monitor system process trees for unexpected child processes spawned by web server workers
• Set up alerts for any new network connections initiated by the web application server

How to Mitigate CVE-2025-25789

Immediate Actions Required

• Identify all FoxCMS v1.2.5 installations in your environment immediately
• Consider temporarily taking affected FoxCMS instances offline until a patch is available or workarounds are implemented
• Implement web application firewall rules to block potentially malicious requests to sitemap endpoints
• Review system logs for any indicators of prior exploitation attempts

Patch Information

At the time of publication, no official vendor patch has been publicly documented. Organizations should monitor the FoxCMS Official Site and FoxCMS Chinese Site for security updates and patch releases. Consider upgrading to a newer version of FoxCMS if available, after verifying that the vulnerability has been addressed.

Workarounds

• Restrict access to the Sitemap.php controller through web server configuration if the sitemap functionality is not required
• Implement IP-based access controls to limit exposure of the FoxCMS installation to trusted networks only
• Deploy a web application firewall with rules specifically targeting code injection attempts in the sitemap endpoint
• Consider implementing additional authentication requirements for accessing administrative or sensitive controller endpoints

# Example: Apache configuration to restrict access to vulnerable endpoint
<Location "/index.php/Sitemap">
    # Deny all access to sitemap controller
    Require all denied
    # Or restrict to specific IP addresses
    # Require ip 192.168.1.0/24
</Location>