CVE-2025-64363 is a vulnerability classified as Remote File Inclusion (RFI) in the SeventhQueen Kleo PHP program, affecting all versions prior to 5.5.0. The vulnerability stems from improper control over the filename parameter used in PHP include or require statements. This lack of validation allows an attacker to supply a crafted filename that points to a remote malicious file, which the server then includes and executes. This can lead to remote code execution, enabling attackers to run arbitrary PHP code on the affected server. The vulnerability is particularly dangerous because it does not require authentication or user interaction, making exploitation straightforward if the vulnerable endpoint is exposed. Although no known exploits have been reported in the wild, the nature of RFI vulnerabilities historically leads to rapid exploitation once disclosed. The vulnerability was published on October 31, 2025, and no CVSS score has been assigned yet. The Kleo product is a PHP-based program, likely used in web applications or content management systems, making it a critical component in web infrastructure for affected organizations. The absence of patch links suggests that users should upgrade to version 5.5.0 or later once available or apply vendor-provided fixes promptly. The vulnerability’s impact includes potential full system compromise, data theft, defacement, or use of the server as a pivot point for further attacks.

For European organizations, the impact of CVE-2025-64363 can be severe. Exploitation can lead to remote code execution, allowing attackers to gain unauthorized access to sensitive data, modify or delete files, and disrupt service availability. Organizations relying on Kleo for web applications or content management may face website defacement, data breaches, or complete server takeover. This can result in reputational damage, regulatory penalties under GDPR for data breaches, and operational downtime. The vulnerability’s ease of exploitation without authentication increases risk, especially for public-facing systems. Attackers could leverage compromised servers to launch further attacks within corporate networks or use them as part of botnets. The lack of known exploits in the wild currently provides a window for proactive mitigation, but the critical nature of the flaw demands urgent attention to prevent potential targeted attacks against European entities.

1. Immediately upgrade SeventhQueen Kleo to version 5.5.0 or later where the vulnerability is fixed. 2. If an upgrade is not immediately possible, apply any vendor-provided patches or workarounds to restrict file inclusion paths. 3. Implement strict input validation and sanitization on all parameters that influence file inclusion or require/include statements to prevent injection of malicious filenames. 4. Deploy Web Application Firewalls (WAFs) with rules to detect and block suspicious file inclusion attempts. 5. Restrict PHP configurations such as disabling allow_url_include and allow_url_fopen to prevent remote file inclusion. 6. Conduct thorough code reviews and security audits of custom code interacting with file inclusion functions. 7. Monitor logs for unusual requests or errors related to file inclusion. 8. Segment and isolate web servers to limit lateral movement in case of compromise. 9. Educate developers and administrators about secure coding practices related to file handling in PHP.