CVE-2025-55055 is a vulnerability classified under CWE-78, indicating improper neutralization of special elements used in OS commands, commonly known as OS command injection. This flaw exists in Rumpus FTP Server version 9.0.12, where user-supplied input is not properly sanitized before being incorporated into operating system commands. An attacker who has authenticated access and can interact with the system may craft malicious input that the server executes at the OS level, potentially leading to arbitrary command execution. The CVSS v3.1 score of 6.8 reflects a medium severity with a vector indicating network attack vector (AV:N), low attack complexity (AC:L), requiring high privileges (PR:H) and user interaction (UI:R). The impact on confidentiality, integrity, and availability is high, meaning successful exploitation could lead to full system compromise, data theft, or service disruption. No public exploits or patches are currently available, increasing the urgency for organizations to implement interim mitigations. The vulnerability was reserved in August 2025 and published in November 2025, indicating recent discovery. Given the nature of FTP servers as critical infrastructure components for file transfer, this vulnerability poses a significant risk if exploited.

For European organizations, this vulnerability could lead to unauthorized command execution on FTP servers, resulting in data breaches, service outages, or lateral movement within networks. Confidential data transferred or stored via the FTP server could be exposed or altered, impacting compliance with GDPR and other data protection regulations. The requirement for high privileges and user interaction reduces the likelihood of widespread automated exploitation but does not eliminate targeted attacks, especially in sectors like finance, healthcare, and government where FTP servers are commonly used. Disruption of FTP services could impact business operations, supply chain communications, and critical infrastructure. The absence of known exploits currently provides a window for proactive defense, but the medium severity and high impact necessitate urgent attention to prevent future exploitation.

European organizations should immediately audit their use of Rumpus FTP Server version 9.0.12 and restrict access to trusted users only, enforcing the principle of least privilege. Implement strict input validation and sanitization on all user inputs interacting with the FTP server to prevent injection of malicious commands. Monitor logs for unusual command execution patterns or failed authentication attempts. Network segmentation should isolate FTP servers from critical internal systems to limit lateral movement. Employ multi-factor authentication to reduce risk from compromised credentials. Until an official patch is released, consider disabling or replacing the vulnerable FTP server with a more secure alternative. Regularly check vendor advisories for patches and apply them promptly. Conduct penetration testing focused on command injection vectors to validate defenses. Additionally, educate users about the risks of interacting with suspicious commands or files on the FTP server.