CVE-2025-4871 is a buffer overflow vulnerability identified in PCMan FTP Server version 2.0.7, specifically within the REST Command Handler component. This vulnerability arises from improper handling of input data, allowing an attacker to overflow a buffer and potentially execute arbitrary code or cause a denial of service. The vulnerability is remotely exploitable without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/AT:N/UI:N/PR:N). The CVSS score of 6.9 classifies it as a medium severity issue, reflecting the potential for partial impact on confidentiality, integrity, and availability, but with some limitations in scope or impact severity. Although no public exploits are currently known to be actively used in the wild, the disclosure of the vulnerability and its technical details increases the risk of exploitation. The lack of available patches at the time of publication further elevates the urgency for affected organizations to implement mitigations. The vulnerability’s exploitation could allow attackers to execute arbitrary code on the FTP server, potentially leading to full system compromise, data theft, or disruption of services. Given that FTP servers often handle sensitive file transfers, this vulnerability poses a significant risk to the confidentiality and integrity of data managed by affected systems.

For European organizations, the exploitation of this vulnerability could lead to unauthorized access to sensitive files and data, disruption of critical file transfer services, and potential lateral movement within internal networks if the compromised server is part of a larger infrastructure. Organizations relying on PCMan FTP Server 2.0.7 for internal or external file transfers may face operational downtime, data breaches, and reputational damage. The medium severity rating suggests that while the vulnerability is serious, exploitation may require specific conditions or may not lead to full system compromise in all cases. However, given the remote and unauthenticated nature of the attack vector, the risk remains substantial. European entities in sectors such as finance, healthcare, manufacturing, and government, which often use FTP servers for data exchange, could be particularly impacted. Additionally, compliance with GDPR and other data protection regulations means that any data breach resulting from this vulnerability could lead to significant legal and financial consequences.

Immediate mitigation steps include disabling the REST Command Handler component if possible or restricting access to the FTP server to trusted networks only, using network-level controls such as firewalls and VPNs. Organizations should monitor network traffic for unusual FTP commands or patterns indicative of exploitation attempts. Implementing intrusion detection/prevention systems (IDS/IPS) with signatures targeting this vulnerability can help detect and block attacks. Since no official patch is currently available, organizations should consider deploying virtual patching via web application firewalls (WAFs) or similar security appliances to intercept and sanitize malicious inputs targeting the REST Command Handler. Regularly updating and auditing FTP server configurations to minimize exposed services and applying the principle of least privilege to service accounts can reduce the attack surface. Planning for an upgrade or migration to a more secure and actively maintained FTP server solution is advisable. Finally, organizations should maintain comprehensive logging and incident response plans to quickly identify and respond to any exploitation attempts.