CVE-2025-54175 is a medium-severity reflected Cross-Site Scripting (XSS) vulnerability identified in OpenSolution's Quick.CMS.EXT version 6.8. The vulnerability arises from improper neutralization of user-supplied input in the 'sFileName' parameter within the thumbnail viewer functionality. Specifically, the application fails to adequately sanitize or encode this parameter before including it in dynamically generated web pages. An attacker can exploit this by crafting a malicious URL containing executable JavaScript code embedded in the 'sFileName' parameter. When a victim opens this URL, the injected script executes in their browser context, potentially allowing the attacker to steal session cookies, perform actions on behalf of the user, or redirect the user to malicious sites. The vendor was notified early but did not provide detailed information about the vulnerability or confirm the full range of affected versions beyond version 6.8, which was tested and confirmed vulnerable. Other versions might also be susceptible but remain untested. The CVSS 4.0 base score is 4.6, reflecting a medium severity level, with attack vector as network (remote), low attack complexity, no privileges required, but user interaction is necessary. The vulnerability does not affect confidentiality, integrity, or availability directly but poses a risk to user session security and trustworthiness of the affected website. No known exploits are currently reported in the wild, and no patches have been published yet.

For European organizations using Quick.CMS.EXT version 6.8, this vulnerability could lead to targeted phishing or session hijacking attacks against their users or administrators. Since the vulnerability is reflected XSS, it requires the victim to click on a malicious link, which could be distributed via email or social engineering campaigns. Successful exploitation could compromise user accounts, leading to unauthorized access to sensitive information or administrative functions. This is particularly concerning for organizations handling personal data under GDPR, as exploitation could result in data breaches and regulatory penalties. Additionally, compromised websites could be used to distribute malware or conduct further attacks, damaging organizational reputation and trust. The lack of vendor response and patch availability increases the risk window for European entities relying on this CMS for their web presence.

Organizations should immediately audit their use of Quick.CMS.EXT, specifically version 6.8, and consider the following mitigations: 1) Implement Web Application Firewall (WAF) rules to detect and block suspicious requests containing malicious scripts in the 'sFileName' parameter. 2) Employ Content Security Policy (CSP) headers to restrict the execution of inline scripts and limit the sources of executable scripts. 3) Educate users and administrators about the risks of clicking on untrusted links and implement email filtering to reduce phishing attempts. 4) If feasible, isolate or disable the thumbnail viewer functionality until a patch is available. 5) Monitor web server logs for unusual requests targeting the vulnerable parameter. 6) Engage with the vendor for updates or consider migrating to alternative CMS platforms with better security track records. 7) Apply rigorous input validation and output encoding in any custom integrations or extensions interacting with Quick.CMS.EXT. These steps go beyond generic advice by focusing on immediate compensating controls and user awareness to reduce exploitation likelihood.