CVE-2025-64363 is a vulnerability identified in the SeventhQueen Kleo PHP program, specifically involving improper control over filenames used in include or require statements. This flaw allows an attacker to perform Remote File Inclusion (RFI) or Local File Inclusion (LFI), enabling them to inject and execute arbitrary PHP code on the affected server. The vulnerability affects all Kleo versions prior to 5.5.0. The root cause is insufficient validation or sanitization of user-supplied input that determines the filename for inclusion, allowing attackers to specify malicious files hosted remotely or locally. Exploiting this vulnerability requires network access and low privileges but does not require user interaction, making it easier to exploit remotely. The CVSS v3.1 score of 7.5 reflects high impact on confidentiality, integrity, and availability, with attack complexity rated as high due to some required conditions but no authentication needed. Although no known exploits are currently reported in the wild, the vulnerability poses a significant risk because successful exploitation can lead to full system compromise, data theft, or service disruption. The vulnerability is categorized under improper control of file inclusion in PHP applications, a common and dangerous web application security issue. The lack of available patches at the time of reporting emphasizes the need for immediate mitigation steps by affected users.

For European organizations, this vulnerability poses a critical risk to web applications running the Kleo product, particularly those that have not upgraded to version 5.5.0 or later. Successful exploitation can lead to remote code execution, allowing attackers to gain unauthorized access to sensitive data, modify or delete information, and disrupt service availability. This can result in data breaches, regulatory non-compliance (e.g., GDPR violations), reputational damage, and financial losses. Organizations operating critical infrastructure or handling sensitive personal or financial data are especially vulnerable. The attack vector being network accessible and requiring only low privileges increases the likelihood of exploitation in exposed environments. The absence of known exploits in the wild currently provides a window for proactive defense, but the high severity score indicates that once exploits emerge, the impact could be severe. European entities with public-facing web services using Kleo are at heightened risk, and the threat landscape may evolve rapidly given the commonality of PHP-based applications in the region.

1. Immediately upgrade all instances of SeventhQueen Kleo to version 5.5.0 or later once available, as this version addresses the vulnerability. 2. Until patching is possible, implement strict input validation and sanitization on all parameters controlling file inclusion to prevent injection of malicious paths. 3. Employ web application firewalls (WAFs) with rules specifically designed to detect and block attempts to exploit file inclusion vulnerabilities. 4. Restrict PHP include paths to trusted directories only, using configuration directives such as open_basedir to limit file system access. 5. Conduct thorough code reviews and security testing focusing on file inclusion logic to identify and remediate similar issues. 6. Monitor logs for suspicious requests that attempt to manipulate include parameters or access unexpected files. 7. Isolate vulnerable applications in segmented network zones to limit potential lateral movement in case of compromise. 8. Educate development and operations teams about secure coding practices related to file inclusion and input handling. 9. Prepare incident response plans to quickly address potential exploitation attempts. 10. Engage with SeventhQueen support or security advisories to stay informed about patches and mitigation updates.