CVE-2025-55056 identifies multiple instances of CWE-79, which is improper neutralization of input during web page generation, resulting in Cross-site Scripting (XSS) vulnerabilities within Rumpus FTP Server version 9.0.12. XSS vulnerabilities occur when an application includes untrusted input in web pages without proper validation or escaping, allowing attackers to inject malicious scripts that execute in the context of a victim's browser. This specific vulnerability requires an attacker to have high privileges (authenticated user) and involves user interaction to trigger the malicious payload, as indicated by the CVSS vector (PR:H/UI:R). The vulnerability affects the web interface of the FTP server, which is used for management and file transfers, potentially exposing session tokens, cookies, or enabling unauthorized actions through script execution. The CVSS score of 4.8 reflects a medium severity, considering the network attack vector, low attack complexity, but the need for authentication and user interaction. No public exploits are currently known, but the vulnerability's presence in a widely used FTP server product necessitates attention. The scope is changed (S:C), meaning the vulnerability can affect resources beyond the initially vulnerable component, increasing potential impact. The lack of available patches at the time of publication requires organizations to implement interim mitigations. This vulnerability highlights the importance of secure coding practices, especially input validation and output encoding in web applications embedded in network services.

For European organizations, exploitation of this vulnerability could lead to unauthorized disclosure of sensitive information such as session cookies or credentials, enabling attackers to impersonate legitimate users or escalate privileges. The integrity of data managed via the FTP server could be compromised by injecting malicious scripts that alter user interactions or data presentation. Although availability is not directly impacted, the resulting compromise could facilitate further attacks, including lateral movement within networks. Organizations in sectors relying heavily on secure file transfers—such as finance, healthcare, and government—may face increased risks of data breaches or compliance violations under GDPR. The requirement for authenticated access limits exposure to internal or trusted users, but insider threats or compromised credentials could still enable exploitation. The need for user interaction reduces the likelihood of automated widespread attacks but does not eliminate targeted phishing or social engineering risks. Overall, the vulnerability poses a moderate risk to confidentiality and integrity, with potential downstream effects on organizational security posture and regulatory compliance.

Immediate mitigation steps include restricting access to the Rumpus FTP Server management interface to trusted networks and users, employing network segmentation and firewall rules to limit exposure. Organizations should enforce strong authentication mechanisms and monitor for unusual login patterns that could indicate compromised credentials. Implementing Content Security Policy (CSP) headers can help mitigate the impact of XSS by restricting script execution sources. Since no patches are currently available, administrators should review and harden web interface configurations, disable unnecessary features, and consider temporary alternative file transfer solutions if feasible. Regularly auditing logs for suspicious activity and educating users about the risks of interacting with unexpected prompts or links can reduce the likelihood of successful exploitation. Once vendor patches are released, prompt application is critical. Additionally, conducting vulnerability scans and penetration tests focusing on web interface security will help identify residual risks. Finally, integrating web application firewalls (WAFs) with XSS detection capabilities can provide an additional layer of defense.