CVE-2025-11750 identifies a security weakness in the langgenius/dify-web authentication process, specifically in version 1.6.0. The vulnerability arises because the system returns different error messages depending on whether a username or email exists in the system. When a login or registration attempt is made with a non-existent username or email, the system responds with an "account not found" message. Conversely, if the username or email exists but the password is incorrect, a different error message is returned. This discrepancy allows an attacker to perform user enumeration by analyzing the error responses, confirming which accounts are valid. User enumeration is a recognized security issue categorized under CWE-544 (Missing Standardized Error Handling Mechanism). Although this vulnerability does not directly expose passwords or sensitive data, it facilitates further attacks such as targeted social engineering, brute force password guessing, or credential stuffing using leaked or reused credentials. The CVSS score is 4.3 (medium severity), reflecting that the attack vector is adjacent network (AV:A), requires no privileges or user interaction, and impacts integrity slightly but not confidentiality or availability. There are no known exploits in the wild, and no patches have been linked yet. The vulnerability highlights the importance of consistent error messaging in authentication workflows to avoid leaking user existence information.

For European organizations, this vulnerability primarily increases the risk of targeted attacks by enabling attackers to identify valid user accounts. This can lead to more effective brute force or credential stuffing attacks, potentially resulting in unauthorized access if users reuse passwords or if weak passwords are employed. While the vulnerability itself does not directly compromise data confidentiality or system availability, it lowers the barrier for attackers to launch subsequent attacks that could lead to data breaches or account takeovers. Organizations in sectors with high-value user accounts, such as finance, healthcare, or government services, could face increased risks. Additionally, the reputational damage and regulatory implications under GDPR for failing to protect user data and authentication mechanisms could be significant if this vulnerability is exploited as part of a broader attack chain.

To mitigate this vulnerability, organizations should implement standardized and generic error messages for authentication failures, ensuring that responses do not reveal whether a username or email exists. For example, always respond with a message like "Invalid username or password" regardless of the underlying cause. Rate limiting and account lockout mechanisms should be enforced to reduce the effectiveness of brute force and enumeration attempts. Multi-factor authentication (MFA) should be deployed to add an additional security layer beyond passwords. Monitoring and alerting on unusual login attempts or enumeration patterns can help detect exploitation attempts early. Additionally, organizations should keep langgenius/dify-web updated and monitor for vendor patches addressing this issue. Security awareness training for users about phishing and social engineering risks can also reduce the impact of targeted attacks facilitated by user enumeration.