Overview
CVE-2025-65403 details a buffer overflow vulnerability found in LightFTP version 2.0. This vulnerability resides within the g_cfg.MaxUsers component and can be exploited by attackers to trigger a Denial of Service (DoS) condition. A crafted input provided to this component overflows the buffer, potentially crashing the application or leading to other unexpected behavior.
Technical Details
The vulnerability stems from insufficient input validation when handling the g_cfg.MaxUsers configuration setting. By providing an input string larger than the allocated buffer for g_cfg.MaxUsers, an attacker can overwrite adjacent memory regions. This can corrupt program data or overwrite critical function pointers, leading to a denial of service. Details of how this input is received are available at the references below.
CVSS Analysis
Currently, the CVSS score for CVE-2025-65403 is not available (N/A). However, given the potential for a Denial of Service attack, it is likely to receive a moderate to high severity rating once a formal assessment is completed. A full CVSS analysis will need to consider attack complexity and whether or not authentication is required for exploitation. It is recommended to monitor vulnerability databases for updates to the CVSS score.
Possible Impact
Successful exploitation of CVE-2025-65403 can lead to a Denial of Service (DoS) condition. This means the LightFTP server becomes unavailable, disrupting legitimate users’ access to the service and potentially affecting business operations reliant on file transfer capabilities. While a simple DoS is the most likely outcome, further investigation may reveal the potential for more severe impacts, such as remote code execution, depending on the architecture and operating system.
Mitigation or Patch Steps
Currently, there is no official patch available from the vendor for LightFTP v2.0 to address CVE-2025-65403. In the absence of a patch, the following mitigation steps are recommended:
- Implement Input Validation: Carefully validate all input provided to the
g_cfg.MaxUserscomponent. Ensure that the input length does not exceed the allocated buffer size. - Use a Web Application Firewall (WAF): A WAF can be configured to filter malicious requests targeting the vulnerable component.
- Consider Alternative Solutions: If feasible, consider migrating to a more actively maintained FTP server solution that receives regular security updates.
- Monitor System Logs: Regularly monitor system logs for any suspicious activity or signs of exploitation attempts.
