CVE-2025-4162 is a critical buffer overflow vulnerability identified in PCMan FTP Server versions up to 2.0.7. The flaw resides within the ASCII Command Handler component, which processes FTP commands sent by clients. Specifically, the vulnerability allows an attacker to send specially crafted commands that overflow a buffer, potentially overwriting adjacent memory. This memory corruption can lead to arbitrary code execution or cause the server to crash, resulting in denial of service. The vulnerability is remotely exploitable without requiring authentication or user interaction, as indicated by the CVSS vector (AV:N/AC:L/PR:N/UI:N). Although the CVSS score is 6.9 (medium severity), the nature of buffer overflow vulnerabilities often implies a risk of remote code execution, which can be severe depending on the exploitability and context. No patches or fixes have been published yet, and no known exploits are currently reported in the wild. The vulnerability affects all versions from 2.0.0 through 2.0.7 of PCMan FTP Server, a product used to provide FTP services, commonly for file transfers in various environments. The lack of authentication requirement and the remote attack vector make this vulnerability particularly dangerous for exposed FTP servers. The ASCII Command Handler is a core component that interprets FTP commands, so exploitation could allow attackers to gain control over the server or disrupt its availability. Given the public disclosure of the exploit details, the risk of exploitation may increase rapidly if mitigations are not applied promptly.

For European organizations, this vulnerability poses a significant threat to any infrastructure relying on PCMan FTP Server for file transfer services. Successful exploitation could lead to unauthorized remote code execution, allowing attackers to compromise the confidentiality and integrity of sensitive data stored or transferred via the FTP server. Additionally, exploitation could cause denial of service, disrupting business operations dependent on FTP services. Sectors such as manufacturing, logistics, and government agencies that use FTP servers for internal or external file exchanges may face operational disruptions or data breaches. The medium CVSS score suggests some limitations in exploit impact or complexity, but the absence of authentication and user interaction requirements increases the attack surface. Organizations with publicly accessible FTP servers are at higher risk, especially if these servers are not segmented or monitored. The potential for lateral movement within networks after initial compromise could further escalate the impact. Given the public availability of exploit information, threat actors may develop automated tools targeting vulnerable servers, increasing the likelihood of attacks. The impact is heightened in environments where patching cycles are slow or where legacy systems prevent upgrading the FTP server software promptly.

1. Immediate mitigation should include isolating PCMan FTP Server instances from direct internet exposure by placing them behind firewalls or VPNs restricting access to trusted IP addresses only. 2. Disable or restrict FTP services if not strictly necessary, or replace them with more secure file transfer protocols such as SFTP or FTPS. 3. Monitor network traffic for unusual FTP command patterns that could indicate exploitation attempts, using IDS/IPS systems with custom rules targeting malformed ASCII commands. 4. Implement strict network segmentation to limit the impact of a compromised FTP server on internal systems. 5. Regularly audit and inventory all FTP servers to identify those running vulnerable versions of PCMan FTP Server. 6. Since no official patches are currently available, consider deploying application-layer mitigations such as input validation proxies or WAF rules that detect and block oversized or malformed FTP commands. 7. Prepare for rapid deployment of patches once released by the vendor, and subscribe to vendor security advisories for updates. 8. Conduct internal awareness campaigns to inform IT and security teams about the vulnerability and the importance of monitoring and mitigation. 9. Employ endpoint detection and response (EDR) solutions on servers hosting PCMan FTP Server to detect anomalous behavior indicative of exploitation.