CVE-2025-4288 is a critical buffer overflow vulnerability identified in PCMan FTP Server version 2.0.7, specifically within the RNFR (Rename From) command handler component. The RNFR command is part of the FTP protocol used to specify the file to be renamed. This vulnerability arises from improper handling of input data length, allowing an attacker to send a specially crafted RNFR command that overflows the buffer allocated for processing this input. Because the vulnerability is remotely exploitable without requiring authentication or user interaction, an attacker can potentially execute arbitrary code or cause a denial of service (DoS) by crashing the FTP server. The CVSS 4.0 base score is 6.9 (medium severity), reflecting the network attack vector, low attack complexity, and no privileges or user interaction required. The impact on confidentiality, integrity, and availability is rated as low individually, but combined they could lead to significant compromise depending on the exploit's payload. No known exploits are currently reported in the wild, and no patches have been linked yet. The disclosure date is May 5, 2025, indicating this is a recent vulnerability. Given the critical nature of buffer overflows and the widespread use of FTP servers in various organizational environments, this vulnerability represents a significant risk if left unmitigated.

For European organizations, the impact of CVE-2025-4288 can be substantial, especially for those relying on PCMan FTP Server 2.0.7 for file transfer operations. Successful exploitation could lead to unauthorized remote code execution, allowing attackers to gain control over affected servers, exfiltrate sensitive data, or disrupt business operations through denial of service. This is particularly concerning for industries with stringent data protection requirements such as finance, healthcare, and government sectors. Additionally, compromised FTP servers could serve as pivot points for lateral movement within corporate networks, increasing the risk of broader network breaches. The medium CVSS score suggests that while exploitation is feasible, the impact on confidentiality, integrity, and availability is somewhat limited individually; however, the ability to execute arbitrary code remotely without authentication elevates the threat level. European organizations with legacy systems or limited patch management capabilities are at higher risk. The lack of an official patch at the time of disclosure necessitates immediate risk mitigation to prevent exploitation.

1. Immediate mitigation should include disabling the RNFR command if possible or restricting FTP server access to trusted IP addresses via firewall rules to limit exposure. 2. Employ network-level protections such as intrusion detection/prevention systems (IDS/IPS) configured to detect anomalous FTP commands or buffer overflow patterns. 3. Monitor FTP server logs closely for unusual RNFR command usage or unexpected connection attempts. 4. If feasible, replace PCMan FTP Server 2.0.7 with a more secure and actively maintained FTP server solution that has no known vulnerabilities. 5. Implement strict network segmentation to isolate FTP servers from critical internal systems, minimizing potential lateral movement. 6. Apply virtual patching via Web Application Firewalls (WAFs) or network security appliances that can block exploit attempts targeting this vulnerability. 7. Stay alert for vendor updates or official patches and apply them promptly once available. 8. Educate IT staff about this vulnerability and ensure incident response plans include steps for handling potential exploitation scenarios.