CVE-2025-56132 identifies a user enumeration vulnerability in the LiquidFiles file transfer server's password reset functionality. The vulnerability arises because the server returns distinguishable responses when an email address exists in the system versus when it does not. This behavior allows unauthenticated attackers to verify valid user accounts by submitting different email addresses and analyzing the server's responses. In versions prior to 4.2, only IP-based rate limiting is implemented, which can be circumvented by distributing requests across multiple IP addresses, such as through proxy rotation, effectively bypassing brute-force protections. Version 4.2 introduces user-based lockout mechanisms that limit brute-force attempts on a per-user basis; however, user enumeration remains possible by default because the application still returns different responses for valid and invalid emails. This vulnerability enables attackers to compile lists of valid user emails, which can be leveraged in subsequent attacks like password spraying or targeted phishing campaigns. The vulnerability affects confidentiality by exposing user existence information, integrity by facilitating unauthorized access attempts, and availability by potentially enabling denial-of-service through account lockouts. The CVSS 3.1 base score of 7.3 (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L) indicates network exploitable, low attack complexity, no privileges or user interaction required, and impacts all three security properties to a limited extent. No patches or exploits in the wild are currently reported, but the vulnerability is publicly disclosed and should be addressed promptly.

For European organizations, this vulnerability poses a significant risk by enabling attackers to enumerate valid user accounts without authentication, which can lead to targeted password spraying, credential stuffing, and phishing attacks. Organizations handling sensitive or regulated data, such as financial institutions, healthcare providers, and government agencies, are particularly vulnerable because exposure of user existence can facilitate unauthorized access attempts and data breaches. The ability to bypass IP-based rate limiting through proxy use increases the likelihood of successful exploitation, potentially leading to account lockouts or service disruption. This can degrade trust in secure file transfer operations and impact business continuity. Additionally, attackers gaining knowledge of valid users can tailor social engineering campaigns, increasing the risk of successful intrusions. The vulnerability also undermines compliance with data protection regulations like GDPR, as it exposes personal data (email addresses) without consent. Overall, the threat can compromise confidentiality, integrity, and availability of critical systems and data within European organizations using LiquidFiles.

To mitigate CVE-2025-56132, organizations should first upgrade to LiquidFiles version 4.2 or later to benefit from user-based lockout mechanisms that limit brute-force attempts on individual accounts. Administrators should configure the application to standardize password reset responses, ensuring that the server returns identical messages regardless of whether an email address exists, thereby preventing attackers from distinguishing valid users. Implementing multi-factor authentication (MFA) for user accounts will reduce the risk of unauthorized access even if valid usernames are discovered. Network-level protections such as Web Application Firewalls (WAFs) can be configured to detect and block suspicious patterns indicative of enumeration attempts, including distributed requests from multiple IPs. Rate limiting should be enhanced beyond IP-based controls to include behavioral analytics and anomaly detection. Regular monitoring and alerting on password reset requests and failed login attempts can help identify exploitation attempts early. Finally, user awareness training should emphasize phishing and social engineering risks stemming from leaked user information.