CVE-2025-53257 is a high-severity vulnerability classified under CWE-98, which pertains to improper control of filenames used in include or require statements within PHP programs. This specific vulnerability affects the Gmedia Photo Gallery software developed by Serhii Pasyuk, up to version 1.23.0. The flaw allows an attacker to perform PHP Local File Inclusion (LFI), which can lead to remote code execution or unauthorized disclosure of sensitive files on the server. The vulnerability arises because the application does not properly validate or sanitize user-supplied input that determines the filename to be included or required by PHP. Consequently, an attacker can manipulate the input to include arbitrary files from the local filesystem, potentially executing malicious code or accessing configuration files, credentials, or other sensitive data. The CVSS 3.1 base score of 7.5 reflects the high impact on confidentiality, integrity, and availability, with network attack vector, high attack complexity, requiring low privileges but no user interaction. Although no known exploits are currently reported in the wild, the vulnerability's nature and impact make it a significant risk. The absence of available patches at the time of publication further increases exposure. This vulnerability is critical for web servers running Gmedia Photo Gallery, especially those accessible over the internet, as exploitation could lead to full system compromise or data breaches.

For European organizations using Gmedia Photo Gallery, this vulnerability poses a substantial risk. Exploitation could lead to unauthorized access to sensitive personal data, including photographs and metadata, potentially violating GDPR and other data protection regulations. The compromise of web servers could also serve as a pivot point for further attacks within corporate networks, impacting business continuity and reputation. Given the high confidentiality, integrity, and availability impacts, organizations could face data breaches, service outages, and regulatory penalties. The attack complexity is high but requires only low privileges, meaning that even limited access to the application could be leveraged for exploitation. This elevates the threat particularly for small and medium enterprises that may lack robust security monitoring. Additionally, the lack of user interaction needed for exploitation means automated attacks or worm-like propagation could be possible if the vulnerability is weaponized. Overall, European entities hosting Gmedia Photo Gallery publicly or internally should consider this a critical security issue with potential legal and operational consequences.

1. Immediate mitigation should include restricting access to the Gmedia Photo Gallery application to trusted networks or VPNs until a patch is available. 2. Employ web application firewalls (WAFs) with custom rules to detect and block suspicious include/require parameter manipulations indicative of LFI attempts. 3. Implement strict input validation and sanitization on all user-supplied parameters, especially those influencing file paths, to prevent directory traversal or arbitrary file inclusion. 4. Use PHP configuration directives such as 'open_basedir' to limit the directories accessible by PHP scripts, reducing the risk of including unintended files. 5. Monitor server logs for unusual requests targeting include parameters or attempts to access sensitive files. 6. Regularly update and patch the Gmedia Photo Gallery software once the vendor releases a fix. 7. Conduct security audits and penetration testing focusing on file inclusion vulnerabilities in web applications. 8. Educate developers and administrators about secure coding practices related to file handling in PHP. These measures, combined, will reduce the attack surface and mitigate exploitation risks until an official patch is deployed.