CVE-2025-5550 is a buffer overflow vulnerability identified in FreeFloat FTP Server version 1.0, specifically within the PBSZ (Protection Buffer Size) command handler component. The PBSZ command is part of the FTP protocol extensions related to secure data channel negotiation, typically used in conjunction with FTP over TLS/SSL. The vulnerability arises when the server improperly handles input data for this command, allowing an attacker to send crafted packets that overflow the buffer allocated for processing the PBSZ command. This buffer overflow can lead to memory corruption, potentially enabling remote code execution or denial of service. The vulnerability is exploitable remotely without any authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). The CVSS 4.0 base score is 6.9, categorized as medium severity, reflecting the potential impact on confidentiality, integrity, and availability, but with some limitations in exploit complexity or impact scope. Although no public exploits are currently known in the wild, the vulnerability has been publicly disclosed, increasing the risk of exploitation attempts. The affected product, FreeFloat FTP Server 1.0, is an FTP server software that may be used in various organizational environments for file transfer services. Given the nature of FTP servers, successful exploitation could allow attackers to execute arbitrary code with the privileges of the FTP server process, potentially leading to full system compromise or disruption of file transfer services.

For European organizations, exploitation of CVE-2025-5550 could have significant consequences, especially for those relying on FreeFloat FTP Server 1.0 for critical file transfer operations. Compromise could lead to unauthorized access to sensitive data, disruption of business processes, and potential lateral movement within internal networks. Organizations in sectors such as finance, manufacturing, healthcare, and government, which often handle sensitive or regulated data, could face data breaches or operational downtime. The remote and unauthenticated nature of the vulnerability increases the risk, as attackers can target exposed FTP servers over the internet without needing credentials. Additionally, disruption of FTP services could impact supply chain communications and data exchange with partners. While the medium severity score suggests some limitations, the potential for remote code execution and system compromise warrants serious attention, particularly in environments where FreeFloat FTP Server is deployed on critical infrastructure or lacks robust network segmentation and monitoring.

To mitigate this vulnerability, European organizations should first identify any instances of FreeFloat FTP Server version 1.0 in their environment. Given the absence of publicly available patches, organizations should consider the following specific actions: 1) Immediately restrict external access to FTP servers by implementing network-level controls such as firewalls or VPNs to limit exposure to untrusted networks. 2) Disable or restrict the use of the PBSZ command if configurable, or disable FTP over TLS if not required, to reduce the attack surface related to this vulnerability. 3) Monitor FTP server logs and network traffic for anomalous PBSZ command usage or unusual connection patterns indicative of exploitation attempts. 4) Employ intrusion detection/prevention systems (IDS/IPS) with updated signatures to detect attempts to exploit buffer overflow conditions in FTP services. 5) Plan for an upgrade or migration to a more secure and actively maintained FTP server solution that addresses this vulnerability. 6) Implement strict network segmentation to isolate FTP servers from critical internal systems, limiting the impact of potential compromise. 7) Conduct regular vulnerability assessments and penetration testing focused on FTP services to identify and remediate weaknesses proactively.