CVE-2023-53928 is a stored cross-site scripting vulnerability identified in PHPFusion version 9.10.30, a PHP-based content management system. The vulnerability resides in the file manager module, where it improperly neutralizes input during web page generation. Specifically, attackers can upload SVG (Scalable Vector Graphics) files that contain embedded JavaScript within <script> tags. When these SVG files are viewed by users through the web interface, the embedded JavaScript executes in the context of the victim’s browser. This execution can lead to session hijacking, theft of cookies, or execution of arbitrary client-side code, potentially enabling further attacks such as phishing or privilege escalation within the web application. The vulnerability requires the attacker to have low privileges (likely a registered user) to upload files, and user interaction is necessary as victims must view the malicious SVG file. The CVSS 4.0 vector indicates network attack vector, low attack complexity, no privileges required (though the vector states PR:L, indicating low privileges), user interaction required, and low impact on confidentiality and integrity but limited impact on availability. No patches or exploits are currently publicly available, but the vulnerability is published and should be addressed promptly. The flaw highlights insufficient sanitization and validation of SVG file content in PHPFusion’s file manager, allowing embedded scripts to persist and execute.

For European organizations using PHPFusion 9.10.30, this vulnerability poses a risk of client-side compromise through stored XSS attacks. Attackers could steal session cookies or credentials, leading to unauthorized access to user accounts or administrative functions. This can result in data breaches, defacement, or further exploitation within the affected web environment. Since PHPFusion is often used by small to medium-sized enterprises and community websites, the impact could be significant for organizations relying on it for public-facing portals or internal collaboration. The vulnerability could also undermine user trust and cause reputational damage. Additionally, if attackers leverage this vector to escalate privileges or implant persistent malware, the overall security posture of the organization could be severely degraded. The medium severity reflects moderate risk but should not be underestimated given the potential for session hijacking and client-side exploitation.

Organizations should immediately verify if they are running PHPFusion version 9.10.30 and restrict file upload permissions to trusted users only. Implement strict validation and sanitization of SVG files, ideally disallowing SVG uploads or stripping out script tags and embedded JavaScript before storage or display. Employ Content Security Policy (CSP) headers to restrict execution of inline scripts and reduce XSS impact. Regularly monitor file uploads and audit logs for suspicious activity. If possible, upgrade to a patched version once available or apply vendor-provided patches. Additionally, educate users to avoid opening suspicious SVG files and consider disabling SVG rendering in browsers or web applications if feasible. Web application firewalls (WAFs) can be tuned to detect and block malicious SVG payloads. Finally, conduct security testing and code reviews focused on input sanitization in file management components.