CVE-2025-5637 is a buffer overflow vulnerability identified in PCMan FTP Server version 2.0.7, specifically within an unspecified function of the SYSTEM Command Handler component. This vulnerability allows an attacker to remotely send crafted input to the FTP server, causing a buffer overflow condition. Buffer overflows occur when data exceeds the allocated buffer size, potentially overwriting adjacent memory and enabling arbitrary code execution or system crashes. The vulnerability is remotely exploitable without requiring authentication or user interaction, increasing its risk profile. The CVSS 4.0 base score is 6.9, indicating a medium severity level, with attack vector network (AV:N), low attack complexity (AC:L), no privileges required (PR:N), and no user interaction (UI:N). The impact on confidentiality, integrity, and availability is rated low, suggesting limited but non-negligible consequences if exploited. Although no public exploit is currently known to be actively used in the wild, the exploit code has been disclosed, raising the risk of future exploitation. The lack of available patches or mitigation links in the provided data indicates that organizations using this FTP server version remain vulnerable until a fix is released or alternative mitigations are applied. PCMan FTP Server is a lightweight FTP server software often used in small to medium-sized environments for file transfer purposes. The SYSTEM Command Handler likely processes commands with elevated privileges, making this vulnerability particularly sensitive as exploitation could lead to unauthorized command execution or denial of service.

For European organizations, exploitation of this vulnerability could lead to unauthorized remote code execution or denial of service on systems running PCMan FTP Server 2.0.7. This could result in disruption of file transfer services, potential data exposure, or compromise of the underlying system integrity. Organizations relying on this FTP server for critical file exchange, especially those in sectors like manufacturing, logistics, or SMBs that commonly use lightweight FTP solutions, could face operational downtime and data integrity issues. Although the CVSS impact metrics are low, the ability to execute arbitrary commands remotely without authentication elevates the risk of lateral movement or further network compromise if attackers leverage this vulnerability as an initial foothold. Additionally, given the public disclosure of exploit code, European entities may experience increased targeted scanning and exploitation attempts. The absence of patches means that affected organizations must rely on network-level protections and configuration changes to mitigate risk, which may not fully prevent exploitation. The impact is heightened in environments where FTP servers are exposed to the internet or untrusted networks without adequate segmentation or monitoring.

1. Immediate mitigation should include restricting external network access to PCMan FTP Server instances, ideally limiting connections to trusted internal IP ranges or VPNs. 2. Employ network-level intrusion detection and prevention systems (IDS/IPS) with signatures or heuristics capable of detecting anomalous FTP SYSTEM command usage or buffer overflow attempts. 3. Disable or restrict the use of the SYSTEM command handler if possible, or configure the FTP server to reject SYSTEM commands from untrusted sources. 4. Monitor FTP server logs for unusual or malformed commands indicative of exploitation attempts. 5. If feasible, replace PCMan FTP Server 2.0.7 with a more secure, actively maintained FTP server solution until an official patch is released. 6. Implement strict network segmentation to isolate FTP servers from critical infrastructure and sensitive data stores. 7. Maintain up-to-date backups of FTP server configurations and data to enable rapid recovery in case of compromise. 8. Educate IT staff to recognize exploitation signs and respond promptly to alerts related to this vulnerability. 9. Follow vendor communications closely for patch releases or official mitigation guidance and apply updates immediately upon availability.