CVE-2025-5547 is a buffer overflow vulnerability identified in FreeFloat FTP Server version 1.0, specifically within the CDUP (Change to Parent Directory) command handler component. Buffer overflow vulnerabilities occur when a program writes more data to a buffer than it can hold, potentially overwriting adjacent memory and leading to unpredictable behavior, including code execution. In this case, the vulnerability can be triggered remotely without any authentication or user interaction, as the attacker can send a specially crafted CDUP command to the FTP server. The vulnerability is classified with a CVSS 4.0 base score of 6.9, indicating a medium severity level. The vector metrics indicate that the attack can be performed remotely (AV:N), requires no privileges (PR:N), no user interaction (UI:N), and no scope change (S:U). The impact on confidentiality, integrity, and availability is rated as low to medium (VC:L, VI:L, VA:L), suggesting that while exploitation could lead to some data compromise or service disruption, it is not expected to cause full system takeover or widespread damage. No known exploits are currently reported in the wild, and no patches or mitigations have been officially released at the time of publication. The vulnerability arises from improper input validation or bounds checking in the CDUP command handler, allowing an attacker to overflow buffers and potentially execute arbitrary code or cause denial of service conditions. Given the nature of FTP servers and their exposure to the internet, this vulnerability represents a significant risk if exploited, especially in environments where FreeFloat FTP Server 1.0 is used without additional protective controls.

For European organizations, the exploitation of this vulnerability could lead to unauthorized access, data leakage, or service disruption of FTP services running FreeFloat FTP Server 1.0. FTP servers often handle sensitive file transfers, including confidential business documents and personal data protected under GDPR. A successful buffer overflow exploit could allow attackers to execute arbitrary code, potentially leading to lateral movement within networks or data exfiltration. The medium CVSS score suggests a moderate risk, but the lack of required authentication and user interaction increases the likelihood of exploitation. Organizations relying on FreeFloat FTP Server for critical file transfer operations may face operational downtime and reputational damage if exploited. Additionally, given the public disclosure of the vulnerability, attackers may develop exploits rapidly, increasing the threat landscape. European entities in sectors such as finance, manufacturing, and government, which often use FTP for legacy systems or internal file transfers, could be particularly vulnerable. The risk is compounded if these servers are internet-facing without adequate network segmentation or intrusion detection systems.

1. Immediate mitigation should include isolating FreeFloat FTP Server 1.0 instances from direct internet exposure using firewalls or VPNs. 2. Disable or restrict the use of the CDUP command if possible, as it is the vector for the vulnerability. 3. Monitor network traffic for anomalous FTP commands or unusually large CDUP requests indicative of exploitation attempts. 4. Employ intrusion detection/prevention systems (IDS/IPS) with signatures or heuristics targeting buffer overflow attempts on FTP services. 5. If feasible, replace FreeFloat FTP Server 1.0 with a more secure, actively maintained FTP server software that has patched this vulnerability. 6. Conduct regular vulnerability scans and penetration tests focusing on FTP services to detect potential exploitation. 7. Implement strict access controls and logging on FTP servers to detect and respond to suspicious activities promptly. 8. Stay updated with vendor advisories for patches or official mitigations and apply them as soon as they become available.